Teacher 21
for
him to catch the ball. Remembering that a slow moving ball can experience
laminar air flow, the ball undergoes
a. extend the slats outward and flaps backward and down.
b. extend slats outward and flaps backward and up.
c. only extend flaps backward and up.
d. only extend slats outward.
a. was zero.
b. was to
the right.
c. was to the left.
d. decreased.
b. are strong buoyant forces
and strong natural convection.
c. are high
pressure gradients and strong conduction.
d. are
strong gravitational forces which effect the shape of the flame.
and
wrapped some sweet potatoes in aluminum foil. The purpose of the
aluminum
foil is to
a. reflect thermal radiation.
b. emit thermal radiation.
c. allow convection to cook the sweet potatoes.
d. allow infrared radiation to cook the sweet potatoes.
as
a filament material is because
room
to the hot outside. By doing this they must convert additional electrical
energy
into thermal energy
a. otherwise it would violate the second law of
thermodynamics.
b. because it is the only way to establish thermal
equilibrium.
c. because it decreases entropy of the overall system.
d. because its converts disordered energy into ordered
energy.
temperature
sensor in it. When he did this he found that the
12 A glass enclosure is necessary when using a tungsten
filament in an
incandescent light bulb because
a. tungsten
must be protected from air or it will burn.
b. it allows
for a cooler operating temperature meaning more visible light.
c.it increases
the sublimation process.
d. it allows heat to be retained around
the filament resulting in brighter light.
Teacher 22
1. An induced drag can occur
when [19]
2. Which advertisement for
golf balls in the Washington Post refers to the effect of replacing the laminar
boundary layer with a turbulent one? [20]
3. Installing a ceiling fan
in a room with a working fireplace [25]
4. In order to overcome the
limitations of a propeller, the Wright brothers could have considered [22]
5. When a Magnus force occurs on a spinning ball, it [ppt]
6. After reading the local kitchen
store ads, a pot set best suited for heat spread might advertise the pot made
with [26]
7. In a geosynchronous
orbit, a satellite is said to be geostationary if it [24]
8. The dominant method of
heat flow inside thermal pane windows and in warming hands over a warm stove is
[27]
9. When Dr. Bloomfield was
able to roast a marshmallow in class using a distant light bulb and mirror
system, he demonstrated that [28]
10. A microscope crashing on
the lab floor is an example of entropy described in the [29]
11.The amount of chemical
potential energy that is turned into work in a typical heat engine is about
[30]
12. Engine knock in an
internal combustion engine occurs when [31]
13. Dr. Bloomfield obtained
a steady, smooth mechanical burn in the milk jug engine by [32]
14. Water evaporation occurs
when [33]
15. A space rocket can best
reach extremely high rates of speed by
Teacher
23
Lecture 22:
1.
It was rainy day so I
decided to park my car in the parking garage. As I was trying to leave the building the wind seem to
dramatically change. The effect of
the wind was that
a.
The wind speed
increased due to the low pressure of it bending inwards.
b.
The wind speed
decreased due to the high pressure of it bending inwards.
c.
The wind speed
decreased due to the low pressure of it bending inwards.
d.
The wind speed increase
due to the low pressure of it bending outwards.
Lecture 23:
2.
You are watching a
shuttle launch on TV and its engines are beginning the chemical reaction with
the rocket fuel. You see the
exhaust get blown out and propel the shuttle upward. When does the rocket begin to accelerate?
a.
It begins when the
gases begin to accelerate.
b.
It begins when the
gases leave the rocket.
c.
It begins when the
gases hit the launch pad.
d.
It begins when the
gases bounce back to the rocket from the launch pad.
Lecture 24:
3.
I was watching a game
of billiards and saw a player hit the 8 ball with his cue ball and an elastic
collision occurred. This caused
the 8 ball to fall into the pocket and the game to be over too soon. What needed to happen for an inelastic
collision to occur?
a.
There needs to be a
third ball involved in the collision to absorb the energy.
b.
The cue ballÕs speed
needs to be reduced drastically.
c.
The cue ball needs to
hit the 8 ball while it sits next to the side of the table.
d.
The surface of the
table should be less smooth to cause friction.
Lecture 25:
4.
It is a very hot day
and you are sweating a great deal.
Sweating is your bodyÕs mechanism to maintain your body
temperature. Explain how this
happens.
a.
When the sweat
evaporates it carries with it thermal energy from your body.
b.
You can only cool down
when the temperature of your surroundings is cooler.
c.
Your sweat adds an
insulating layer around your body.
d.
Sweat is the
condensation of water on your skin from the warm humid air.
Lecture 26:
5.
A recipe for brownies
recommends that you use a dark surface metal pan to bake it compared to a
lighter one. Why would a black
surface be a better conductor?
a.
Black objects will
absorb all visible energy and emit it as thermal radiation.
b.
The atoms in black
objects are closer allowing thermal energy to be uniform.
c.
Black objects have a
lower energy of activation.
d.
The recommendation is
misleading because they are promoting their pans.
6.
One of the stunt tricks
you commonly see is people walking barefoot across a bed of red hot coals of
wood. If you walk quickly enough,
you wonÕt suffer any pain. Why?
a.
Coals of wood are poor
conductors of heat.
b.
The coals of wood are
actually emitting mostly visible radiation.
c.
Your foot emits more
infrared and thermal energy than the rest of you.
d.
The moisture on your
feet will insulate you from any type of hot.
Lecture
27:
7.
A larger incandescent
light bulb with the same voltage as the smaller one will
a.
Be brighter.
b.
Have the same
luminescence.
c.
Be dimmer.
d.
Have radiation emitted
closer to the longer wavelength.
8.
I need coffee first
thing in the morning and I tend to pour it immediately into my mug. Sometimes I am in a hurry to get the
first sip, but I donÕt want to burn my tongue so I have learned to pour in the
cream first to cool it down and I donÕt have to wait. Why does this work?
a.
The cream lightens the
coffee and will radiate its thermal energy faster.
b.
It only works if you
chill the cream.
c.
The atoms of cream will
bind with coffee atoms and change its thermal energy.
d.
The cream is less dense
than the coffee so it will distribute through uniformily.
Lecture
28:
9.
Dolphins can
communicate further apart from one another. This can occur because
a.
Sound travels faster in
a denser medium like water than in air.
b.
Dolphins use a much
higher pitch when communicating.
c.
The atoms that make up
the liquid medium can vibrate faster.
d.
When sound travels in
air objects in its way often stop it.
10.
There are four
incandescent lights connected to the chandelier. One has a broken bulb, the second has the bulb and the
filament broken, the third has only the filament broken and the fourth is still
intact. Which of the bulbs will still
emit electromagnetic radiation when you turn on the switch?
a.
All four lights will
still emit electromagnetic radiation.
b.
Only the light with
everything intact will emit electromagnetic radiation.
c.
Only the two lights
with the filament intact will emit the radiation.
d.
Only the two lights
with the bulb intact will emit the radiation.
Lecture 29:
11.
If you do your own
ironing, you may have learned a trick of licking your fingers first and briefly
touching the iron to judge if it is hot enough to begin. You donÕt get burned because
a.
The thermal energy is
used to vaporize the moisture not burn your finger.
b.
The iron was not hot
enough.
c.
Your fingers are much
cooler and can absorb the thermal energy briefly.
d.
The iron and your
finger reached a thermal equilibrium quickly.
Lecture 30:
12.
The most energy
efficient time to run your air conditioner at maximum is to run it during the
evening. Your summer cooling bill
will be much less because
a.
the work needed to
remove the thermal energy from inside is less.
b.
most people run their
heat pump during the day so it is cheaper at night.
c.
The thermal energy of
the house in the evening is much less.
d.
You can also open the
windows so the cooler evening air comes in.
Lecture
31:
13. In an internal combustion engine the piston allows
a.
The gases to be
compressed and turn it into heat to do work.
b.
Greater changes in
pressure inside the engine so the gas does work.
c.
Just a place for the
fuel to mix.
d.
Work to be done so that
the working fluid flows to an evaporator.
Lecture
32:
14.
The diesel engine is
different from the internal combustion engine by
a. Not mixing the fuel with the air before it compresses
it.
b. Allowing lower compressions so that the engine has
time to ignite.
c. The hot air that is compressed does more work on the
piston.
d. It can burn its fuel at lower temperature so that
less heat is loss.
15.
When you are heating
your car on a cold day, it heats up faster if you close the vent to the outside
circulation because
a. Any heat in the car will flow out to the cooler air.
b. Condensation can form on the outside of the car to
insulate it.
c. The outside of the car stays cool in thermal
equilibrium with the air.
d. The engine has to compress less air to produce
thermal radiation.
Teacher 24
Lecture 25
a. The ball would go through the ring
because the hole would expand.
b. The ball would not go through the ring
because the hole would contract.
c. The ball would go through the ring
because the ball would expand.
d. Nothing would happen to the ball and
the ring.
a. There is an increased amount of
chemical potential energy than the original molecules.
b. Chemical energy is converted into
thermal energy.
c. The temperature is set by the thermal
kinetic energy.
d. Conduction, convection, and radiation
are all used in the heat transfer process.
Lecture 26
why this was
preferred over a pot with a stainless steal bottom. Which one of the following
is not true.
a. Atoms at the cold end of the copper
move more vicariously carrying heat throughout.
b. Electrons are not confined, which means
they are a good carrier of thermal energy.
c. More heat flows through the copper than
the stainless steel.
d. The copper bottom pot provides for
uniform cooking than the stainless steel pot.
It
due to the absence of
a. radiation.
b. conduction.
c. convection.
d. reflection.
Lecture
27
5. What would happen if one would plug in
a light with a 150-watt incandescent bulb without the
glass
bulb?
a. It would not light, because the filament would catch
on fire.
b. It would continue to light, but much brighter than
with the glass bulb.
c. Nothing would happen.
d. It would continue to light, but much dimmer than with
the glass bulb.
6. Energy put into an incandescent bulb,
it emitted as
a. mostly infrared radiation with some
visible light.
b. mostly visible light with some infrared
radiation.
c. visible light only.
d. infrared radiation only.
Lecture
28
7. What causes the filament in an
incandescent bulb to separate?
a. sublimation
b. condensation
c. conduction
d. convection
8. Which of the following statements is
not true of halogen bulbs?
a. Center shifts from the ultraviolet end
of the spectrum to the visible end of the spectrum.
b. Center shifts from the infrared end of
the spectrum to the visible end of the spectrum.
c. They are more energy efficient, living
longer than incandescent bulbs.
d. They are brighter per unit of surface
area of the filament.
Lecture
29
9. What do air conditioners and
automobiles have in common?
a. They both are considered heat machines.
b. They use work to transfer heat from
cold to hot.
c. They use the flow of heat from hot to
cold to do work.
d. They both are considered to be heat
pumps.
10. The second law of thermodynamics states
that entropy
a. never decreases.
b. never increases.
c. never redistributes.
d. never approaches zero.
Lecture
30
11. The most disordered arrangement of a
given collection of materials is
a. Total homogeneous mixture of the
materials and everything is at the same temperature.
b. Total heterogeneous mixture of the
materials and everything is at the same temperature.
c. Total homogeneous mixture of the
materials and everything is at different temperatures.
d. Total heterogeneous mixture of the materials
and everything is at different temperatures.
12. Which of the following is not a
characteristic of a dehumidifier?
a. The energy that is released is less
than the energy taken out of the air.
b. It separates water from the air.
c. Thermal energy is soaked up, getting cold and then released.
d. Entropy is reduced.
Lecture 31
13. Automobiles
a. create useful work out of heat.
b. convert useful work into heat.
c. use work to move heat from cold to hot.
d. diverts some heat as it flows from cold
to hot.
14. In an automobile engine, one of the
following provides energy to the engine:
a. induction stroke
b. compression stroke
c. power stroke
d. exhaust stroke
Lecture
32
15. Which of the following is true about
diesel engines?
a. Pure air is compressed to tremendous
pressures.
b. They are able to burn fuel at lower
temperatures making it more efficient.
c. The fuel air mixture lights to do work.
d. Thermal energy is converted into
chemical energy providing high efficiency.
Teacher
25
Teacher 27
1. Lecture 19
I donÕt play tennis, but
IÕve seen it. It is possible to
cause a tennis ball to accelerate toward the earth faster than gravity pulls
it. This is a very useful shot if
done well. In order to do this,
you must:
A. Put topspin on the ball,
which deflects the wake upward, forcing the ball downward.
B. Put topspin on the ball,
which deflects the wake downward, pulling the ball downward.
C. Put backspin on the ball,
which deflects the wake downward, forcing the ball downward.
D. Put backspin on the ball,
which deflects the wake upward, forcing the ball downward.
2. Lecture 20
I donÕt play golf either,
but IÕve seen this, too. Golf
balls today could not possibly fly as far as they do without the dimples on
their surface. The dimples serve
to break up the boundary layer of air, which allows the ball to fly through the
air with less drag. This is
because:
A. The dimples cause a small turbulent wake, which increases
the pressure behind the ball.
B. The dimples cause a small viscous drag, which decreases the
pressure behind the ball.
C. The dimples decrease viscous drag because they donÕt project
out of the surface of the ball.
D. The dimples reduce the average radius of the ball, giving it
a smaller profile to hit the air.
3. Lecture 21
When flying to Albuquerque
recently, I noticed the wing flaps stick out very far to increase the surface
area of the wing. The wing extends
forward and backward, to become much ÒfatterÓ, and sometimes these surfaces
retract to become thinner. Which
statement summarizes the purpose of these shape-changes?
A. The flap extends to
deflect more air downward, to give more lift at slow speeds.
B. The flap extends to increase the surface area of the control
surface, for high speed stability.
C. The extended flaps make the plane less dense, increasing the
buoyant force of the air.
D. The flaps stick out into the air, to create turbulence so the
tail flaps do not experience drag.
4. Lecture 22
On the plane I took to
Australia, I noticed that the intake of the engines were huge! Engines of a jumbo jet have a huge
diameter, sometimes nearly 10 feet across. The effect of this huge intake is that a large amount of air
passes through the engine. Why is
it a good idea to have a large mass of air processed by the engine?
A. Pushing a larger mass of air is more efficient than
increasing the speed of the air.
B. Taking in a huge amount of air is needed to have enough
compression for combustion.
C. Much of the air is used for cooling of the engine parts by
convection, preventing melting.
D. The mass of air is actually independent of the force of
thrust created by the engine.
5.Lecture 24
Jay Leno has a jet-powered
motorcycle, and I have seen rocket-powered cars break speed records. Yet there are reasons why rockets or
jets are used in particular situations.
What is the difference between rockets and jets?
A. Rockets carry both fuel and oxygen, so no atmospheric oxygen
is needed, as it is for jets.
B. Rockets have a smoother shape, so they are used for
faster-moving situations.
C. Jets require more fuel to achieve equal momentum to a
rocket, so they are less efficient.
D. All jets have more moving parts, so rockets are used where
maintenance would be difficult.
6.Lecture 25
Mrs. Anderson (my mom) once
left an aluminum pot of boiling water on the stove until the water boiled away
and the pot then melted on the coils!
Why did the pot melt only after the water was gone? Why did the pot not melt sooner?
A. The water absorbs the heat given to the pot by conduction as
quickly as the heat is supplied.
B. The water conducts the coolness of the air to the pot,
preventing a temperature rise.
C. Because water is clear, the pot radiates heat away so it
doesnÕt melt.
D. The boiling water vapor exited the pot, convected to the
coils and cooled them.
7. Lecture 26
Dr. Bloomfield demonstrated
a natural-gas powered steam engine that moves a hammer. In my class, I have an electrically
powered steam engine that lights a light bulb. It is obvious how the natural-gas powered steam engine gets
heat to the water in the boiler.
It is less obvious how my electrically powered steam engine does
so. Why is the water heating up?
A. A special filament has high resistance to electricity, so
friction between electrons releases heat.
B. The electricity is conducted through the water, which heats
it up.
C. The boiler is superfluous in this engine. The electricity turns a motor which
drives the system.
D. The electrons are jumping off the wire into the water,
creating friction which heats the water.
8. An amazing demo in class is to hold a flame to a piece of
paper for a long time, and not have it light. A piece of paper wrapped around a thick metal bar will not
ignite when touched with a lit match because
A. energy is conducted away
by the metal, preventing the paper from reaching ignition temperature.
B. the paper reflects the
energy, and is a poor absorber of energy because it is white.
C. the bar keeps the paper
relatively cool because it stays at room temperature.
D. oxygen (air) only touches
one side of the paper, which is not enough to support combustion.
9. Lecture 28
In my apartment, we have
both heat in the winter, and air conditioning in the summer. We like to keep the temperature at 70
degrees F, which is maybe 20 degrees lower than the average hot day, and 20
degrees warmer than the average cold winter day. Strangely, the bills are not even close to being the
same. Which bill, cooling or
heating is greater, and why?
A. Cooling: In trying to decrease entropy, work must be done,
costing extra energy.
B. Heating: Raw materials are being burned up, which are very
expensive.
C. Cooling: The friction of moving parts in the a/c unit works
against the cooling effect.
D. Heating: In order to burn fuel for heat, a huge amount of
input energy is needed.
10. Lecture 29
The air conditioning in our
high school has much to be desired, so we have hired laborers to hand-power
manual coolers. Dr. Bloomfield
described an air conditioning system whereby you pump air into a jar, which
cools when the top pops off. In
this process, thermal energy was added to the universe, even though the jar
cooled. Where did this thermal
energy come from?
A. The work the laborers did in pumping the air into the jar
resulted in thermal energy.
B. The thermal energy taken out of the room increased as the
air in the jar was compressed.
C. The friction of the moving parts of the pump created thermal
energy.
D. The energy used by the person in pumping raises their
temperature, giving off energy.
11. Lecture 31
I find that my nifty little
VW GTI is particularly peppy on a cool morning, right after starting the
engine. One might think that
warming up the engine produces better performance, but this has not been my
observation. The cooler the engine
is, the better it performs. What
is a possible explanation?
A. Entropy change between
cool intake air and hot exhaust air is greater, so more work is extracted.
B. At higher temperature,
the metal parts expand and leaks occur within the engine.
C. Warmer air is less dense,
so under compression it doesnÕt supply as much pressure.
D. Warmer air can hold more
water vapor. This water vapor
reduces the efficiency of combustion.
12. Dr. Bloomfield demonstrated a
natural-gas powered steam engine that moves a hammer. In my class, I have an electrically powered steam engine
that lights a light bulb. Would it
be possible to have the electricity produced power the engine itself? Could it be a perpetual energy machine?
A. No, because much energy is lost to heat by friction
throughout the process.
B. Yes, as long as the wires are superconductors, and have no
resistance to electrical flow.
C. No, because the electrons that are pushed in the wires leave
the filament, taking energy away.
D. No, the light bulb doesnÕt need as much energy as the
boiler, so it gives back less than it got.
13. Lecture 32
I have a peppy 4 cylinder
engine in my VW. I wouldnÕt mind
it being a little peppier, so IÕm thinking of putting a turbo on it. WhatÕs the idea behind the
turbocharger?
A. Compressed air entering the cylinder can be mixed with more
fuel, so more work can be done.
B. The turbo compresses air and shoots it out the rear of the
car, like a jet engine, pushing the car.
C. The turbo pushes air into the engine, which pushes hard on
the piston directly, so it goes faster.
D. It pulls exhaust out of the cylinder, so the engine itself
doesnÕt have to do that work, saving energy.
14. Lecture 33
A fun demonstration in my
class is to cause a soda can to implode, using the effects of temperature
change on water. By heating water
inside a can, then turning the can upside down in a bucket of water, the can
instantly crushes itself. Why?
A. Boiled water becomes less dense vapor. In a bucket, the
vapor condenses and sucks in the can.
B. Everything expands when heated, and shrinks when
cooled. The air inside the can
shrank.
C. The water vapor, like any gas, contracts when cooled by the
bucket water, pulling the sides in.
D. Gravity causes the water in the can to pour into the
bucket. The water leaving pulls
the sides in.
15. Something I only had to learn once was
not to fool around with a pressure cooker. Steam burns at 100 degrees C are more damaging than burns
caused by a similar mass of boiling water at 100 degrees C because steam
A. has more energy per gram
than water, because it absorbed extra energy to become a gas.
B. occupies more space than
water, so it covers more of your skin.
C. has a higher temperature
than boiling water. Since it is no
longer liquid, it must be hotter.
D. penetrates your skin
better than water. In the gas
phase, vapor can get into all the small spaces.
[1] Karl
is sitting behind a pick-up truck at a stoplight, and he notices an automatic
clothes washer in the back of the truck. The front of the washer is facing
toward the rear of the truck. The light turns green, and the truck takes off
with Karl following. As they increase their speed down the highway, Karl
notices that the lid on the washer begins to rise up as the truck travels
faster. This is because
[a] the
high pressure air inside the washer overcomes the low pressure air moving across the lid.
[b] the
turbulent air from the top of the truck creates a whirlwind vortex and vacuum
that lifts the lid.
[c] the
region of high pressure air directly behind the truck exerts an upward force
pushing on the lid.
[d] the
lid rises up attempting to slow the speed of the truck and maintain constant
momentum.
[2] Formula
1 racecars traditionally have inverted airfoils (i.e., curved side down)
positioned on the front and rear of the car. The purpose of this is
[a] to
produce a reverse lift to push the wheels down for added traction to keep the
car on the track.
[b] to
extend the turbulent flow further behind the car to discourage other cars from
crowding close.
[c] to
extend the region of laminar flow further behind the car to prevent dangerous
turbulence.
[d] to
create a region of increased high pressure behind the car to help push it
faster.
[3] A
common sales promotion gimmick for vacuum cleaners during the summer is the
Òfloating beach ballÓ. The ball is held suspended in space, spinning on an
upward column of air exhausted from a vacuum cleaner hose. Even though the
exhaust hose and air column are pointing at an angle of 45 degrees from
vertical, the ball cannot escape from the column of blowing air because
[a] the
high-pressure still air outside pushes the ball back into the lower-pressure,
moving air column.
[b] the
ball experiences a buoyant force from the more dense moving air that maintains
its position.
[c] the
higher-pressure, moving air inside the column produces a turbulent vortex that
traps the ball.
[d] the
spinning ball produces a pressure difference on opposite sides that always
pushes upward.
[4] A
helicopter rotor is basically a system of rapidly rotating airfoils. The force
generated to lift the helicopter is the result of
[a] the
rotor creating high pressure air below the airfoils that pushes them and the
helicopter upward.
[b] the
rotor pushing a jet of air downwards, which pushes the helicopter upward by
action/reaction.
[c] the
rotor producing a strong vortex vacuum above the airfoils that pulls the
helicopter upward.
[d] the
rotor producing a shock wave of high density air that creates a large upward
buoyant force.
[5] The
feathers on an arrow are placed at the rear of the shaft in order to
[a] utilize
the forces exerted by the moving air to keep the tip of the arrow pointed
forward
[b] change
the center of mass of the arrow to increase the lift force while decreasing
drag.
[c] generate
a region of high-pressure air behind the arrow to push it forward faster.
[d] dissipate
thermal energy generated by the air friction against the shaft of the arrow.
[6] DonnieÕs
toy rocket has a hollow plastic body. The rocket is half-filled with water and
attached to a hand-pump, which pressurizes the air inside. When the rocket is
released from the pump, the rocket shoots upward. The purpose of the water is
[a] to
act as the action/reaction exhaust mass pushed out by the high-pressure air.
[b] to
prevent the high pressure air from escaping from the rocket too quickly.
[c] to
keep the center of mass of the rocket low to prevent it from tumbling.
[d] to
give the pressurized air something to push against as it leaves the rocket.
[7] As part of a self-improvement class, Kathy spent one
day in a motivational workshop. After six hours of activities with her peers
designed to build trust and personal confidence, the culminating activity was a
fire-walking exercise. She was
able to successfully walk quickly barefooted across a 20-feet bed of glowing
wood coals. Which of the following explains why Kathy was not burned?
[a] Wood,
even as hot, glowing coals, is a very poor conductor and little heat reached
her skin.
[b] The
wood coals, while appearing red hot, had lost most of their thermal energy
during burning.
[c] Most
of the heat in the coals was transferred to the air by radiation, leaving none
to reach Kathy.
[d] The
convection currents above the coals dissipated the heat, cooling them to body
temperature.
[8] Which
of the following statements is not true in reference to the Stefan-Boltzmann equation for power radiation from
a hot object.
[a] The
amount of power radiated is inversely proportional to the surface area of the
object.
[b] The
temperature must be measured in kelvin units.
[c] The
power radiated is directly proportional to the fourth power of the temperature.
[d] The
emissivity or efficiency of the radiating materialÕs surface is a factor in the
power radiation.
[9] The
Space Shuttle typically orbits the Earth at an approximate altitude of 200
miles. The reason that it can orbit without falling back to the surface of the
Earth is because
[a] its
very large velocity carries it so far horizontally that the EarthÕs surface
curves away under it.
[b] its
orbit is so high that there is no gravity at that altitude to pull it back to
Earth.
[c] there
is no air in space to produce gravity, and the Shuttle experiences no force to
pull it down.
[d] gravity
is produced by the EarthÕs rotation, and the Shuttle in space does not feel any
rotation.
[10] Professor
Zarkoff placed an ice cube in the bottom of a large glass test tube and pushed
a tight copper coil down on top of it to hold the ice cube at the bottom. He
filled the test tube with water and put it in a wooden test tube rack. Using a
propane torch, he began heating the top of the test tube. The water at the top
began boiling vigorously, but the ice cube did not melt because
[a] most
of the heat was carried upward by the convection currents instead of moving
down to the ice
[b] the
copper coil conducted the heat away from the ice into the glass.
[c] the
wood in the test tube rack is an insulator and trapped the heat before it
reached the ice.
[d] the
copper coil heated the water so quickly that it began to boil at a much lower
temperature.
[11] Rattlesnakes belong to a class of snakes called pit
vipers. These snakes can detect and strike prey even at night in virtually no
light because
[a] the
pits below their eyes are infrared sensitive and can detect the heat radiation
from the animal.
[b] the
pits below their eyes amplify the visible light that is present and send the
image to its brain.
[c] the
pits below their eyes detect the warm convection currents rising from the
animalÕs body.
[d] the
pits collect the heat radiation emitted by the snakeÕs tongue that reflects
from the preyÕs body.
[12] Long-life
incandescent light bulbs have an extended life beyond regular light bulbs
because
[a] they
operate at a lower temperature and emit less light, thus slowing the burnout of
the filament.
[b] they
have a vacuum inside the bulb, which prevents the filament from oxidizing and
burning out.
[c] they
use pure carbon filaments instead of tungsten because carbon has a higher
melting point.
[d] they
use high pressure oxygen to make the filament a more efficient emitter and
extend its life.
[13] Zero-Point
Industries announced its invention of
a revolutionary, high-efficiency heat pump to heat homes in winter. It claims
that on a 0o F day, the pump can extract 1000 joules of thermal
energy from the ground using only 100 joules of electrical energy, and then put
1500 joules of heat into the house. Their claim is clearly false. It violates
the Laws of Thermodynamics because
[a] their
heat pump created energy by putting out more heat than the total energy going
into it.
[b] there
is no extra thermal energy in the cold ground in winter that can be used.
[c] moving
heat from a cold region to a warmer region would cause the total entropy to
increase.
[d] thermodynamics
forbids non-thermal energy like electricity from being converted to heat.
[14] ÒI have a
new theoryÓ, said the Hatter. ÒIf I can scramble an egg by stirring it
clockwise, then I can unscramble it by stirring it counterclockwise. What do
you think of that?Ó
ÒWell,Ó
said Alice smiling, ÒthatÕs the silliest idea you have had yet. If you want to know the truth,Ó she
said, Òit would never work. You could never stir the egg back together
becauseÉÓ
[a] that
would force the entropy of the egg to decrease, which is never, ever likely to
happen.
[b] once
you have mixed up the egg, the old molecules have been destroyed and new ones
created.
[c] the
original energy of the egg has been destroyed in the mixing, and it canÕt be
used again.
[d] the
mixing energy has converted some of the mass to heat, so all of the mass is no
longer there.
[15] A diesel
engine is different from a standard four-cycle internal combustion engine
primarily because
[a] its
compression cycle is so strong that the hot fuel-air mixture ignites without
using a spark plug.
[b] extra
fuel is injected during the power stroke to create a hotter explosion.
[c] each
piston has an two ignitions during the four cycles.
[d] the
fuel is injected at a very low pressure which makes it burn hotter than a
standard engine.
Teacher 29
1. When you purchase a can of soda gases
are visible inside the can. If you
open your cold soda and begin drinking it but donÕt finish it, saving if for
later isnÕt a good idea. What
causes you open soda to become ÒflatÓ?
a. An increase in temperature of the soda and a decrease
in pressure.
b. A decrease in temperature of the soda and an increase
in pressure.
c. An increase in both temperature and pressure of the
soda.
d. A decrease in both temperature and pressure of the
soda.
2. Most often weather conditions occur due to the relative
humidity in the air. We can
predict that it will rain when
a. The relative humidity exceeds 100% and warm, moist
air becomes cool.
b. The relative humidity exceeds 100% and cool, dry air
warms.
c. The relative humidity falls below 100% and warm,
moist air becomes cools.
d. The relative humidity falls below 100% and cool, dry
air warms.
3. Why isnÕt water a gas at room temperature such as other
comparable gases such as oxygen, propane or methane?
a. The Hydrogen bonds in the water are very strong.
b. The Hydrogen bonds in the water are very weak.
c. There are very few bonds present in the water.
d. The water bonds donÕt bond with one another well.
4. Old train engines have whistles they blow to warn passers-by
of their presence. What does
blowing the whistle do to the energy that is powering the train?
a. Blowing the whistle takes energy away from the train.
b. Blowing the whistle adds energy to the train.
c. Blowing the whistle does not affect the energy of the
train.
d. Blowing the whistle uses a different type of energy
than the train.
5. How does the head of an engine
break?
a. The activation energy from the spark plug pushes the
piston too far out of the cylinder.
b. The spark plug does not activate the fuel and no
potential energy is released.
c. The compression step of the cycle doesnÕt properly
prepare the fuel for ignition.
d. The activation energy only pushes the piston a
minimal distance in the cylinder.
6. Why is a 6-cylinder engine more beneficial than a 4-cylinder
engine when merging into a busy highway?
a. There are 1 ½ cylinders providing energy to
the car allowing it to accelerate more.
b. It is not.
The 4-cylinder engine is more advantageous than the 6-cylinder engine.
c. The 6-cylinder engine is lighter than the 4-cylinder
engine.
d. The 4-cylinder engine uses more gas than the
6-cylinder engine.
7. After running a dehumidifier
the temperature of a room
a. Increases
b. Decreases
c. DoesnÕt change
d. Varies upon its location in the house
8. In a stuffy classroom
during the winter, students are compelled to open the windows. Why isnÕt this an effective way to cool
the room?
a. Heat flows from warm to cool, causing the heat to
flow to the outside.
b. Heat flows from cool to warm, causing the cool air to
flow from the outside to the inside.
c. Heat will not flow in any direction.
d. It depends on the location of the classroom inside
the school building.
9. Is it easier to cause
disorder in an ordered room more than in a room with present disorder?
a. Disorder will affect order more than it would affect
disorder
b. Disorder will affect disorder more than it would
affect order.
c. Order will affect disorder more than it would affect
order.
d. Order will affect present order more than it would
affect disorder.
10. Is it more likely for
someone to suffer heat stroke on a warm, humid day rather than a hot dry day?
a. ItÕs more likely to suffer heat stroke on a warm,
humid day.
b. ItÕs more likely to suffer heat stroke on a warm, dry
day.
c. ItÕs more likely to suffer heat stroke on a cool,
humid day.
d. ItÕs more likely to suffer heat stroke on a cool, dry
day.
11.Does using an air
conditioner or a heater in a car use more fuel?
a. Using an air conditioner uses more fuel.
b. Using a heater uses more fuel.
c. Both use the same amount of fuel.
d. Fuel consumption depends on the type of car.
12. When cleaning up a broken light bulb
there is a trace of powder inside the glass. Why is there powder present?
a. Powder makes the light less harsh to the naked eye.
b. Powder makes the light bulb last longer.
c. Powder is releases from the heated glass.
d. Powder is a by-product of the filament.
13. Halogen light bulbs are
more energy efficient than incandescent lights because
a. They have a higher fraction of visible light than
infrared light.
b. They have a lower fraction of visible light than
infrared light.
c. They have the same amount of visible light as
infrared light.
d. They arenÕt more energy efficient than incandescent
light bulbs.
14. In a 3-way light bulb there is a long
filament and a short filament.
Describe the on/off pattern when the short filament breaks (when
starting from the original off position).
a. Off, on, on, off
b. Off, on, off, on
c. On, off, on, off
d. On, on, off, off
15. Computer labs and libraries in schools
are often kept at very cool temperatures.
This protects the computers from
a. Becoming too hot and causing the computers to become
good conductors and self-destruct.
b. Becoming too cool and causing the computers to become
good conductors and self-destruct.
c. Becoming too hot and causing the computers to become
poor conductors and self-destruct.
d. Becoming too cool and causing the computers to become
poor conductors and self-destruct.
Teacher 30
1. Which of the following
statements is true of the constriction that a working fluid encounters as it
enters the evaporator in an air conditioner?
a) it initiates a drop in
both pressure and temperature in the working fluid
b) it initiates a rise in
pressure and a drop in temperature in the working fluid
c) it initiates a drop in
pressure and a rise in temperature in the working fluid
d) it initiates a rise in
both pressure and temperature in the working fluid
2. A turbofan engine can be
more efficient than a turbojet engine if it É
a) moves more air backwards
at lower speeds
b) moves more air backwards
at higher speeds
c) moves less air backwards
at lower speeds
d) moves less air backwards
at higher speeds
3. In what direction will
the lift force provided by an airplane propeller point if the plane is flying
horizontally?
a) forwards (in the
direction of motion)
b) backwards (opposite the
direction of motion)
c) upwards
d) downwards
4. You are in a building
with three rooms. When a door is
opened between rooms A and B, no heat flows between them. When a door is opened between rooms B
and C, no heat flows between them.
You feel certain that no heat will flow if a door is opened between
rooms A and C because of the É
a) Zeroth Law of
Thermodynamics
b) First Law of
Thermodynamics
c) Second Law of
Thermodynamics
d) Third Law of
Thermodynamics
5. A satellite is in a
stable circular orbit around the Earth.
The time it takes the satellite to make one complete orbit around the
Earth is NOT dependent on which of the following quantities?
a) the mass of the satellite
b) the mass of the Earth
c) the center-to-center
distance between the satellite and the Earth
d) the gravitational
constant
6. You have been given the
task of filling a small space between two metal plates with a material such
that one plate will be as thermally isolated as possible from the other
plate. Which of the following
materials would be the best choice?
a) stainless steel
b) aluminum
c) copper
d) silver
7. You have an insulated
piston system with a gas inside it.
The system is initially in equilibrium. Heat cannot flow into or out of the system. If you physically compress the gas by
pushing inward on the piston, which of the following statements is true?
a) work is done on the
system and the internal energy of the gas increases
b) work is done on the
system and the internal energy of the gas decreases
c) work is done on the
system and the internal energy of the gas is unchanged
d) work is done by the
system and the internal energy of the gas increases
8. Body A has twice the
absolute temperature of Body B.
Which of the following statements is true of the thermal radiation
emitted by the two bodies?
a) The thermal radiation
emitted by Body A is 16 times that emitted by Body B
b) The thermal radiation
emitted by Body A is 8 times that emitted by Body B
c) The thermal radiation
emitted by Body A is 4 times that emitted by Body B
d) The thermal radiation
emitted by Body A is 2 times that emitted by Body B
9. Which of the following
statements is generally true of the products as compared to the reactants
involved in the burning of hydrocarbons?
a) the molecules produced
have less chemical potential energy and are more stable
b) the molecules produced
have less chemical potential energy and are less stable
c) the molecules produced
have more chemical potential energy and are more stable
d) the molecules produced
have more chemical potential energy and are less stable
10. At a temperature of 2500
degrees Celsius, the majority of the electromagnetic radiation emitted by a
black object is É
a) infrared radiation
b) red light
c) yellow light
d) bright yellow-white light
11. You hold your hand to
the side of a hot light bulb. You
feel the heat of the bulb mainly due to which of the following processes?
a) radiation
b) conduction
c) convection
d) a combination of
conduction and convection
12. A three-way light bulb
has the following lighting possibilities once installed in a given lamp
assembly: A = off, B = dim, C = bright, and D = very bright. If the larger filament in the bulb
burns out, which of the following gives the new sequence of lighting
possibilities?
a) A = off, B = dim, C =
off, and D = dim
b) A = off, B = dim, C =
dim, and D = dim
c) A = off, B = off, C =
dim, and D = bright
d) A = off, B = dim, C =
bright, and D = bright
13. Which stroke/strokes in
a typical 4-stroke engine have work being done on the engine by the air-gas
mixture?
a) the power stroke only
b) the compression stroke
only
c) the power and induction
strokes
d) the power, induction, and
exhaust strokes
14. A one cylinder 4-stroke
engine is idling at 2400 RPMÕs.
Approximately how many power strokes occur each second?
a) 20
b) 40
c) 80
d) 600
15. Which of the following
best describes the changes that take place to the working fluid as it passes
through the condenser of an air conditioner?
a) it changes from a hot
high-pressure gas into a warm low-pressure fluid
b) it changes from a warm
low-pressure fluid into a hot high-pressure gas
c) it changes from a hot
high-pressure fluid into a warm low-pressure gas
d) it changes from a warm
low-pressure gas into a warm low pressure fluid
Teacher 31
1) What is one way for an airplane to slow down quickly?
a)
Create a bigger
turbulent wake
b)
Create less of a
turbulent wake
c)
Point the nose of the
airplane at greater angle to the horizon
d)
Lower the engineÕs
power
2) A shuttle lifts off the ground by:
a)
Expelling fuel and the
conservation of momentum
b)
Burning fuel and the
conservation of energy
c)
Expelling fuel hitting
the ground and this fuel doing work on the shuttle
d)
Burning fuel and
chemical potential energy changing into kinetic energy
3) In the cartoon, Futurama, the robot, Bender is flung from the outside of his
spaceship while it was going as fast as possible. His shipmates claim theyÕll never catch up to him because he
will go on forever. Bender manages
to slow himself down and eventually come to a stop. How?
a)
He starts to throw
items away from him, in the direction he was traveling.
b)
He starts to throw
items away from him, in the area from which he just came.
c)
Bender flails crazily
until he comes to a stop.
d)
Bender waits patiently
until he comes to a stop naturally.
4) Why are airplanes not allowed to take off closer than
90 seconds apart?
a)
Time is needed to
prevent getting caught in the wingtip vortices of the previous plane.
b)
The planes cannot go
any faster.
c)
The computers in charge
of timing cannot reset quicker.
d)
Planes have different
speeds and they would be more likely to run into each other.
5) Why do candles not burn by themselves in outer space?
a)
There is little
gravity, so there is no buoyant force.
b)
There is not enough
oxygen in the spacecraft.
c)
The convection currents
are too strong and blow the candle out.
d)
Since gravity is lower
than on earth, the buoyant force is too strong.
6) While at a fancy dinner party, the host is burned
while serving hot soup with a silver serving spoon. What was the cause of his burn?
a)
The hot soup conducted
heat all through the spoon.
b)
The hot soup and the
cool spoon used convection to transfer heat.
c)
The spoon radiated
energy through itself to the handle.
d)
The spoon is not a good
conductor, so it must have started off hot and remained that way.
7) After performing a demonstration of the electrolysis
of water in class, there is one test tube full of hydrogen gas and another half
full of oxygen gas. If a lit match
is brought close to the hydrogen gas, the gas ignites. What did the match provide?
a)
Activation energy
b)
Kinetic energy
c)
Gravitational potential
energy
d)
Chemical potential
energy
8) Why are copper pipes more commonly used than aluminum
pipes?
a)
Copper has more loose
outer electrons, so it is a better conductor of heat.
b)
Aluminum has more loose
outer electrons, so it is a worse conductor of heat.
c)
Copper provides the
best convection of heat.
d)
Because of its color, copper
radiates better than aluminum.
9) Liz, moving into her own apartment for the first
time, is excited to try out her new pots and pans. She decides to try making pancakes in a pan first. She burns the first one and notices
that the coils from her burner can be seen on the pancake. Every pancake after that, even if not
burned, shows the coils from the burner and is unevenly cooked. What is her problem?
a)
Liz bought stainless
steel pans, which are not good conductors of heat.
b)
LizÕs new pans are
copper, which is a very good conductor of heat.
c)
The burners in LizÕs
new apartment do not heat evenly.
d)
The pans are a
stainless steel-copper combination. This stops food from cooking evenly.
10) While in a restaurant, I order a cup of coffee and it
arrives before I am ready to drink it.
In order to have the coffee as hot as possible when I am ready to drink
it, when should I add cream to the coffee?
a)
Right away because the
cream makes the coffee a lighter color so it will radiate less heat.
b)
Right away because the
convection currents from the cream and coffee will settle sooner.
c)
Directly before
drinking because the cream will just cool the coffee without any other effects.
d)
Right before drinking
as the two will be closer in temperature and will take longer to cool.
11) While looking in a mirror in the bathroom (which has
incandescent lights), my lipstick looks much redder than it does while outside
and looking in a mirror. Why is
this?
a)
Incandescent lights are
stronger in lower frequencies than higher frequencies.
b)
Incandescent lights are
stronger in higher frequencies than lower frequencies.
c)
The sun emphasizes the
blues more than the reds.
d)
The incandescent lights
are too hot to show blue colors brightly.
12) When a three-way light bulb starts to burn out, why
does it not become a two way light bulb?
a)
One of the two
filaments has sublimed, so it is impossible to have two power levels.
b)
Two of the three
filaments have sublimed, so it is impossible to have two power levels.
c)
The filament shortened,
making it impossible to have two power levels.
d)
All of the filaments
disconnected, making it impossible to two power levels.
13) Water put into a freezer compartment in your
refrigerator goes to a state of less molecular disorder when it freezes. Is this an exception to the entropy
principle?
a)
No, work was put into
the system.
b)
Yes, heat was taken out
of the system.
c)
No, no heat or work was
transferred to or from the system.
d)
Yes, there was a
transfer of heat or work.
14) Why are the coils on the backs of refrigerators hot?
a)
When the fluid in the
refrigerator condenses, it gives off energy to the coils and then the air.
b)
When the fluid in the
refrigerator condenses, it takes energy in from the air to the coils.
c)
When the fluid in the
refrigerator evaporates, it gives off energy to the coils and then the air.
d)
When the fluid in the
refrigerator evaporates, it takes energy in from the air to the coils.
15) When leaving a swimming pool on a dry day in Arizona,
I get goose bumps and cold, even though the air temperature is pretty
warm. Why?
a)
The water droplets leaving
my skin take energy with them.
b)
The water droplets on
my skin cool it because of their moisture.
c)
The water droplets have
condensed on my skin, making it cooler.
d)
The water droplets are
breaking their hydrogen and oxygen bonds, taking energy with them.
Teacher 33
1. During a game of beach
volleyball, my sister hits the beach ball giving it a good amount of backspin
(top turns back toward hitter).
Her opponent, who is not very physics savvy, hits where he expects the
ball and is surprised that ball is not there. Which is most likely
a. The ball is higher than
he expected because wake deflection and lift.
b. The ball is higher than
he expected because of the wind.
c. The ball is lower than he
expected because of wake deflection and lift.
d. The ball is lower than he
expected because of pressure drag.
2. A turbulent wake behind a
ball occurs because as the boundary layer of a fluid moves from low pressure
above toward high pressure at the back
a. it accelerates backward,
slows down, loses energy, and breaks away from surface.
b. it accelerates forward,
slows down, loses energy, and breaks away from surface.
c. it accelerates forward,
and flies off the ball at a tremendous speed.
d. it breaks NewtonÕs second
law of motion.
3. It is not a good idea for
a commercial jet to take off and land at 600 mph. In order to get more lift at lower speeds during take-off
and landing, a commercial jet can change the shape of it wings. Which of the following is correct:
a. The wing becomes larger
and more strongly curved and the minimum safe airspeed drops.
b. The wing becomes larger
and more strongly curved and the minimum safe airspeed rises.
c. The wing becomes smaller
and less curved and the minimum safe airspeed drops.
d. The wing becomes smaller
and less curved and the minimum safe airspeed drops.
4. When hot air leaves the
jet engine, it is traveling much faster than before it entered but is at
approximately its original pressure.
There is also a greater volume of air leaving than entered. What accounts for the increase in
volume?
a. The same number of hot
air molecules can occupy a larger space and maintain the pressure.
b. The compressor adds air
molecules.
c. The added fuel creates
more air molecules.
d. The turbines suck in
additional air.
5. The primary difference
between rocket propulsion and jet engine propulsion is:
a. A jet engine is pushed by
outside air; a rocket is pushed by material it carries with it.
b. A jet engine burns fuel
and a rocket engine does not.
c. A jet engine is pushed by
outside air; a rocket engine must push off the ground.
d. A jet engine can
accelerate faster than a rocket engine.
6. When the space shuttle is
outside of the earthÕs atmosphere, it controls stability by:
a. directing the rocket
exhaust.
b. tilting the wings.
c. extending flaps to change
the shape of the shuttle.
d. the natural stability of
the fins at the back of the shuttle.
7. The amount of work
required to break a chemical bond is
a. the same as the amount of
energy lost by the atoms when the bond was formed.
b. the same as the amount of
energy gained by the atoms when the bond was formed.
c. more than the amount of
work required to make the bond.
d. less than the amount of
work required to make the bond.
8. My husband will sometimes
warm my hands by placing my cold hand between his two warm hands. What is causing my hand to warm?
a. Conduction between his
hands and mine, and blocking thermal radiation away from my hand.
b. Conduction only.
c. The cold from my hand
flows into his by conduction.
d. Blocking of thermal
radiation only.
9. The last time I made
rice, I discovered that some of the rice was burned/stuck on the bottom of the
pan in the shape of a coil - the same shape as the heating element on the
stove. Assuming the temperature of
the element was not too hot, what conclusion could I draw about the pan I used?
a. The pan is a poor
conductor of heat.
b. The pan did not allow for
proper convection of heat.
c. The pan increased the
thermal radiation of the rice.
d. The pan and the rice were
at thermal equilibrium.
10. Which of the following
statements is NOT true about black objects at a specific temperature?
a. The object emits
electromagnetic waves at one specific wavelength and color.
b. The object emits
electromagnetic waves over a range of wavelengths.
c. Most of the thermal
radiation emitted is not visible.
d. As the temperature
increases, the range of wavelengths shifts toward shorter.
11. On a recent trip to a
local home improvement store, I looked at two different 60-Watt light
bulbs. The first bulb claimed 780
lumens and 1000 hours of light. If
the second bulb claimed 2000 hours of light, which of the following is the most
likely output?
a. 640 lumens
b. 780 lumens
c. 1000 lumens
d. 1500 lumens
12. Microwave ovens heat
food using thermal radiation with wavelengths of about 1 millimeter to 1
meter. Disregarding safety issues,
why wonÕt food wrapped in aluminum foil heat in a microwave?
a. The shiny foil will
reflect the electromagnetic waves and they wonÕt reach the food.
b. The foil is a poor
conductor of heat.
c. The foil disrupts the
convection of hot air in the microwave oven.
d. The foil absorbs all of the
thermal radiation and does not transfer it to the food.
13. During our recent
spring-cleaning, I had my husband pull out the refrigerator and vacuum
thoroughly the back of the unit as well as the surfaces around the
refrigerator. We also removed the
accumulation of shopping bags from the sides of the unit. How will this affect the working of the
unit?
a. This should improve the
flow of heat away from the condenser.
b. This should improve how
the flow of heat into the evaporator.
c. The working fluid will be
able to flow more quickly.
d. The working fluid will
now flow more slowly.
14. What is the function of
the spark plug in an internal combustion engine?
a. It supplies the activation energy to ignite the fuel/air
mixture.
b. It lowers the pressure of the fuel/air mixture.
c. It supplies the additional energy needed to comply with the
second law of thermodynamics.
d. It keeps the engine from knocking.
15. In a four-stroke engine,
during which stroke or strokes is work done on the engine?
a. only during the power stroke
b. during the power and induction strokes
c. during the compression and exhaust strokes
d. during the compression, induction and exhaust strokes
Teacher 34
1. Which of the following would NOT lower the Reynolds
number? (lecture 19)
A. High density
B. Slow flow
C. Small obstacles
D. High viscosity
2. Drag force is most closely related to (lecture 19)
A. surface area
B. volume
C. mass
D. density
3. Professor Bloomfield talks about perfect laminar flow
in his lecture on airplanes. Chalk particles are able to experience perfect
laminar flow because (lecture 20)
A.
size
B.
chemical composition
C.
Ratio of Oxygen to Nitrogen
D.
Density of Nitrogen
4. Altitude is primarily effected by two components.
(lecture 20)
A.
speed and angle of attack
B.
speed and induced drag
C.
angle of attack and wing shape
D.
wing shape and speed
5. Physics can be used in many sports to give you a
competitive edge. In tennis, which
of the following physics concepts can aid a player? (lecture 21)
A.
top spin
B.
bottom spin
C.
vertical spin
E. horizontal torque
6. Rockets are actually a simple expansion of a basic
law in physics. Which law do
Rockets exemplify? (lecture 24)
A. NewtonÕs Third Law
B. NewtonÕs First Law
C. HookeÕs Law
D. NewtonÕs Second Law
7. During a turn, a tricycleÕs most significant problem
with equilibrium is caused by (ch.5)
A.
Torque exerted by friction
B.
Center of mass raised higher than normal
C.
Static instability
D. Ratio of the viscosity between the
wheels and the ground
8. Braking on a bicycle changes energy from one form to
another. Which change below is
what happens during braking? (ch.5)
A.
kinetic energy to thermal energy
B.
kinetic energy into potential energy
C. thermal energy into kinetic
energy
D. potential energy into
kinetic energy
9. Which of the following is NOT produced by a hot
filament? (lecture 27)
A.
gamma rays
B.
visible light rays
C.
ultraviolet rays
D.
infared
10. Which of the following
statements accurately explains why a filament is black? (lecture 27)
A.
it absorbs and emits light efficiently with an emissivity near 1
B.
it emits light efficiently with an emissivity near 0
C.
it absorbs and emits light with an emissivity near 0
D.
it absorbs light efficiently with no emissivity
11. Jane is trying to build
her own light bulb. She is trying
to select the appropriate filament.
She wants to produce the lowest watt possible. Which filament should she select? (lecture 28)
A.
short, thin filament
B.
short, thick filament
C.
long, thin filament
D.
long, thick filament
12. In a turbo jet engine,
air actually increases in speed from the entering speed to the exiting
speed. This results in a net
increase in the speed of the air.
This is a result of an increase in the volume of the air caused by
(lecture 22)
A.
addition of fuel to the air
B.
the size of the engine
C.
the diameter of the turbine
D.
the pressure of the air
13. Which of the following is INCORRECTLY
matched.(lecture 25)
A.
gas-conduction
B.
solid-conduction
C.
liquid-convection
D.
wavesÐraditaion
14. A candle cannot have a flame in the
space shuttle because of the absence of
(lecture 25)
A.
buoyancy
B.
Oxygen
C.
drag pressure
D. Nitrogen to Oxygen ratio
15. Which of the following
statements about entropy are INCORRECT? (lecture 29)
A.
system must maintain thermal equilibrium
B.
can be moved or transferred
C.
defined as an objectÕs disorder
D.
in isolated system it never decreases
Teacher 35
1. Backspin on a ball makes it defy gravity. Why is this? [19]
a.
two lift forces are directed upward to oppose gravity
b.
spinning reduces the viscous drag force on the ball
c.
the Magnus and wave deflection forces cancel each other
d.
drag and lift forces are in the same direction
2. Viscous drag and pressure drag Ð how do these change on an
object as airflow changes from
laminar to turbulent? [20]
a.
viscous drag is constant, pressure drag increases
b.
viscous increases, pressure decreases
c.
viscous constant, pressure decreases
d.
both increase
3. Golf ball dimples make the ball travel farther because- [20]
a.
boundary layer turbulence adds energy to airflow around ball
b.
dimples make boundary layer turbulent airflow more laminar
c.
turbulence in boundary layer increases airflow separation around ball
d.
dimples reduce viscous drag
4. Fan blades and propellers both turn and move air. Which best describes the relationship
between the two? [22]
a.
propellers are airfoils, fan blades are not
b.
fan blades are the aerodynamic opposites of propellers
c.
they are essentially the same aerodynamically
d.
propellers move much more air than fan blades of same size and rotation speed
5. My son commented on the airplane wings (struts and flaps)
ÒbreakingÓ just before take-off
on our last airplane flight. Why do the struts and flaps ÒbreakÓ
before take-off? [21]
a.
to increase the wingsÕ curvature, and generate more lift
b.
to widen the wing, and create less turbulence
c.
to speed up the process of vortex shedding
d.
struts and flaps lessen the possibility of stalling
6. What physical purpose does rocket fuel serve in propelling a
rocket into space? [23]
a.
it provides downward momentum that propels the rocket upward
b.
it provides upward momentum that propels the rocket upward
c.
it burns to provide chemical KE to overcome gravitational PE.
d. it converts chemical KE to PE to lift
the rocket
7. What is needed for a satellite to maintain a geosynchronous
orbit? [24]
a.
an eastward orbital velocity and a given radius of orbit
b.
an eastward orbital velocity and an acceleration to overcome gravity
c.
an acceleration to overcome gravity and a given height of orbit
d.
a westward orbital velocity and a given radius of orbit
8. Why does a sealed dropped candle go out as it falls? [24]
a.
air loses its buoyant force in free fall, and oxygen is not pulled into the
flame
b.
carbon dioxide gas descends to put out the flame
c.
the flame is pulled downward and is put out by liquid wax
d.
the temperature drops below the flash point for wax
9. An electron microscope can ÒseeÓ smaller things than an
optical microscope can because- [26]
a.
energized electrons emit smaller wavelengths of radiation than visible light
does
b.
energized electrons can be absorbed by very small things, light cannot
c.
energized electrons emit lower frequency radiation than visible light does
d.
visible light does not refract as well as energy from electrons
10. Why are halogen bulbs more energy
efficient than regular incandescent bulbs? [27]
a.
halogens are hotter, so more of the energy is in the visible spectrum
b.
the halogen and the filament emit visible light
c.
they use less electrical energy per time, that is lower wattage
d.
they have a chemical PE that is converted to light energy
11. What makes regular incandescent light
bulbs ÒdieÓ or Òburn outÓ? [27]
a. tungsten filament sublimes, and the filament degrades
b. tungsten filament gets too hot and breaks
c. nichrome filament melts and degrades
d. nichrome filament sublimes and filament
degrades
12. Heat can move (be transferred) from
areas of less thermal energy to areas of more thermal
energy if- [29]
a.
heat transferred is accompanied by the creation of disordered energy
b.
heat transferred is accompanied by the creation of ordered energy
c.
heat is transferred as potential energy
d.
heat is transferred, but entropy decreases
13. In a four-stroke engine, what happens
during the compression stroke? [31]
a.
fuel and air temperature and
pressure increase in the engineÕs cylinder
b.
fuel and air are mixed and pushed into the engineÕs cylinder
c.
burned fuel and air are pushed out the engineÕs cylinder
d.
positive work is done on the engine
14. In a diesel engine, ignition occurs
when- [31]
a.
fuel is injected into very hot, pressurized air
b.
very hot air is injected into pressurized fuel
c.
a Òglow plugÓ is exposed to a very hot , pressurized fuel/air mixture
d. fuel is heated well beyond its flash
point temperature, and exposed to air
15. Nitrous oxide is used in engines of
certain drag-racing cars. What
part does it play in
combustion? [32]
a.
it is a liquid that easily supports combustion of fuels
b.
it is a very combustible liquid
c.
it is a very compressible gas that supports combustion
d.
it easily decomposes in a highly exothermic reaction
Teacher 36
1. Your physics teacher is trying to wake up two
sleeping students sitting side by side by throwing a ball at them. She has two different balls Ð one with
twice the mass as the other. Which
ball requires more energy from the teacher if both balls have equal momentum?
a. The small ball -- it must
move faster than the large ball.
b. The large ball -- it has
more mass than the small ball.
c. Both balls require the
same amount of energy.
d. The large ball -- the
teacher must throw it harder to overcome its inertia.
2. NASA frequently launches rockets into space. What propels a rocket as it lifts off
the launch pad and what propels the rocket after it leaves the EarthÕs
atmosphere?
a. The act of pushing gas
out of the rocket propels it in both situations.
b. The launch pad propels it
on Earth and its inertia propels it in space.
c. Burning fuel propels it
both on Earth and in space.
d. The launch pad propels it
on Earth and burning fuel propels it in space.
3. The toy rockets we launched on the football field
have fins at the back and a pointed tip at the nose. The fins are important because
a. they catch the wind so
the nose stays in the front as the rocket flies.
b. they add mass to the
rocket.
c. they help to stabilize
the rocket on the launch pad.
d. They are added for looks
only and are not important in the flying of the rocket.
4. An astronaut had her 30th birthday while
on a mission in space. Her fellow
astronauts wanted to celebrate with cake and ice cream. They stuck candles in the cake and
tried to light them but they wouldnÕt burn. Why not?
a. They were in freefall Ð
no buoyant force to help the flame burn upward.
b. There was no oxygen to
burn, so the candles wouldnÕt even light.
c. They were in freefall Ð
so the candles wouldnÕt even stick into the cake.
d. The horizontal motion of
the spacecraft caused the flame to go out.
5. My husband and I looked at a lot of different pots
and pans when we were registering for wedding gifts. He wanted to get copper pots, but I wanted stainless steel
ones that would be easy to clean.
We compromised and got stainless steel pots with copper bottoms. Physics-ly speaking, why are copper
pots better than stainless steel ones?
a. Copper is a good
conductor of heat because it easily sheds its electrons.
b. Copper is a more stable
metal. It does not easily shed its
electrons.
c. Stainless steel pots tend
to be thinner than copper ones and can melt.
d. Copper is not an alloy,
and is therefore safer for cooking.
6. Your physics teacher wanted to demonstrate
convection cells in boiling water.
Unfortunately, she did not have a glass beaker, so she used her paper
coffee cup from Burger King. You
cringed as she set the water-filled paper cup just above the flame of a Bunsen
burner. To your surprise, the cup
didnÕt burn, but the water boiled.
Why?
a. The water near the bottom
transfers heat away from the bottom of the cup.
b. The flame is not touching
the cup, so it doesnÕt catch on fire Ð no activation energy.
c. The wax coating on the
cup transfers heat away from the cup by melting.
d. Boiling water requires
less heat than burning paper.
7. My grandparents installed a woodstove in the den to
provide additional heat for my grandfather, who gets cold easily. My grandfather complained that it
wasnÕt putting out as much heat as he would like, so my grandmother installed a
ceiling fan above the stove. Why
would she do something like that?
a. The fan pushes hot air
toward the floor, increasing heat transferred by convection.
b. The fan stirs the air,
increasing heat transferred by conduction.
c. The fan helps push the
denser, warm air downward near the floor.
d. The fan helps pull the
denser, cool air upward away from the floor.
8. Which of the following statements is true
about black objects?
a. Black objects absorb all
light and are perfect at emitting thermal radiation.
b. Black objects absorb all
light but do not emit thermal radiation.
c. Black objects mix visible
light and reflect all of the colors, making them look black.
d. Black objects absorb all
thermal radiation around them but do not emit any.
9. I have a gecko in my classroom. He has a light shining down into his
cage to help him stay warm. How
does the light bulb keep the gecko warm?
a. The light from the bulb
transfers heat by radiation to the gecko Ð making him warm.
b. The bulb warms the air
around it. Warm air transfers heat
to the gecko by convection.
c. The bulb warms the sand
in the cage, which then warms the gecko due to conduction.
d. The bulb warms the air
around it. Warm air radiates all
around the gecko, warming it.
10. Optical pyrometers are used to tell how hot an
object is by measuring the amount of light being emitted from the object. Optical pyrometers can only be used to
measure objects hot enough to emit light from the red end of the visible light
spectrum. They work best for
objects
a. with a black surface,
such as a cast iron skillet.
b. that are clear, such as
glass.
c. with a shiny surface,
such as a mirror.
d. with a white surface,
such as the porcelain surface on a sink or counter top.
11. Dehumidifiers are a type of heat pump. They transfer heat from
a. a colder region to a
hotter region, converting ordered energy to thermal energy.
b. a hotter region to a
colder region, converting ordered energy to thermal energy.
c. a colder region to a
hotter region, converting thermal energy to ordered energy.
d. a hotter region to a
colder region, converting thermal energy to ordered energy.
12. Air conditioning units convert ordered energy to
thermal energy. Which part of the
air conditioning unit provides the ordered energy necessary for this transfer
of energy?
a. The compressor provides
the ordered energy.
b. The evaporator provides
the ordered energy.
c. The condenser provides
the ordered energy.
d. The working fluid
provides the ordered energy.
13. My grandfather did all of the repairs on my car
before he passed away six years ago.
I wish I paid attention when he explained how a four-stroke engine
works. I remember that burning gas
provides the work to power the car.
During which stroke does the burning gas do the work that powers the
car?
a. Work is done to power the
car during the power stroke.
b. Work is done to power the
car during the compression stroke.
c. Work is done to power the
car during the induction stroke.
d. Work is done to power the
car during the exhaust stroke.
14. Both manual and automatic transmissions must have
some way of transferring torque from the engine to the drive shaft. How do manual transmissions do this?
a. The clutch uses friction
to transfer torque.
b. Moving fluids are used to
transfer torque.
c. A flywheel spins a belt,
which transfers torque to the drive shaft.
d. Cylinders transfer torque
during the power stroke.
15. Most of the students in this physics class have
boiled water or have seen boiling water in a pot on a stove. How can you tell when water is boiling?
a. Bubbles will form in the
water when it starts to boil.
b. Bubbles will form on the
sides of the pot when the water starts to boil.
c. A thermometer inserted
into the water will read 100 C.
d. A thermometer inserted
into the water will read higher than 100 C.
Teacher 37
1.
My daughter and I are
volunteer stream watch testers in our county. One of the tests we do is flow rate. It is a simple test of timing a dye
through the water for a certain distance.
We are careful not to test in an area where the water bed narrows
because of large rocks or tree limbs.
Why is this?
A)
The waterÕs speed
increases where the stream narrows.
B)
The waterÕs speed
decreases where the stream narrows.
C)
The dye would be pulled
under the water due to turbulent flow.
D)
The pressure of the
water would increase in this area.
2.
Why would a large ball
moving through the air have a larger turbulent wake, than a smaller ball moving
at the same speed?
A) The large ball has more viscous and pressure drag due
to its surface area.
B) The large ball has a larger density than the smaller
ball.
C) The large ball would slow down faster.
D) Overall, the small ball experiences no pressure drag.
3.
After hearing Professor
Bloomfield talk about why bicyclists stay together in races reminded me of
birds flying in V formation. I
deduced that the reason the birds fly in such a formation is to
A) Make use of the air pockets created by the birdÕs
wings to reduce fatigue.
B) So that they have more buoyant force.
C) To achieve more lift on each wing.
D) To make use of friction caused by air resistance.
4.
What happens to air
that flows through a large duct in the ceiling of a home, and travel through a
smaller diameter passage way just before entering a large room?
A) The pressure of the air decreases and its speed
increases.
B) The pressure of the air increases and its speed
increases.
C) Less air molecules pass through the smaller passage
way.
D) More air molecules pass through the smaller passage
way/
5.
What is the Newtonian
view about why airplanes have lift?
A) The wings push the air down, and the air pushes up on
the wing.
B) The air makes an inward bend on top of the wing, and
outward under the wing.
C) The net force is greater because of air resistance.
D) The plane has a lot of inertia and fights air
resistance.
6.
Why is it difficult, if
not impossible to light a candle aboard a space shuttle?
A)
There can be no
combustion with oxygen without sufficient gravity present.
B)
There can be no
combustion without oxygen present.
C)
The buoyant force of
flame is greater than its weight.
D)
It is impossible to
light a match or a lighter aboard a space shuttle.
7.
What does it mean to
say that when two atoms share electrons they form a bond and the bond is an
indication of missing energy?
a. The atoms release chemical potential energy at a
specific distance apart.
b. The atoms hit each other and bounce back loosing
momentum.
c. Nuclear energy is lost when the bond is formed.
d. The electrons of both atoms repel each other and
loose energy.
8.
Which of the following
is NOT an example of a device that transfers thermal energy against its natural
direction?
a. A woodstove
b. An air conditioner
c. A dehumidifier
d. A refrigerator
9.
I have a dehumidifier
in my basement to remove excess moisture from the air. The air feels less moist, but a
little heat is released into the room from the dehumidifier. Why?
a. Excess
heat is released due to consuming electrical energy.
b. The working fluid is gaining heat when it is
evaporated into a gas.
c. Electricity is used so that the dehumidifier acts
like a electronic heat pump
d. There is
most likely a leak in the evaporator coils.
10.
In the summer our
family enjoys making ice cream in our small quart size ice cream maker. After putting in the ice you add rock
salt. What is the reason for
adding salt to already cold ice?
A) To decrease the freezing temperature of the ice cream
B) To have a hard surface for the ice crystals to grow
on
C) To increase the temperature of the ice cream mixture
for ease of stirring
D) To increase the amount of time that the ice melts
11.
In one of the demos in
lecture 25, Dr. Bloomfield put a paper cup of water over a burner and left it
there to boil. Why didnÕt the
paper cup melt in the flame before the water started boiling?
A) Thermal energy was transferred very fast from the
paper to the water.
B) Thermal energy was transferred from the flame
directly to the water.
C) The melting temperature of the paper cup was above
the flame temperature.
D) The burnerÕs temperature was not high enough to
affect both a solid and a liquid.
12.
In my lamps at home, I
can tell when a light bulb is in its last days because there is a dark black
smudge on the top inside of the bulb.
What does that tell me?
A) That the tungsten filament is wearing away due to
sublimation
B) That there are combustion reactions occurring in the
bulb.
C) The inert gas inside of the bulb is depleting.
D) There is less radiation into the visible range of the
electromagnetic spectrum.
13.
Which of the following
are terrible conductors of heat?
A) Air
B) Copper wire
C) Aluminum pot
D) Woodstoves
14.
While lecturing in class I occasionally use a laser pen. One of my students asked me if the
light was hot. I told her no,
because a laser pen works more like a
A) Fluorescent bulb than an incandescent bulb.
B) An incandescent bulb than a fluorescent bulb.
C) An incandescent bulb that uses 130 volts instead of
120 volts.
D) Halogen light bulb.
14.
While shopping for an
automobile, I noticed on the window sales sticker, whether the car is a
4-cylinder, 6-cylinder or 8-cylinder.
What difference does it make?
A) The 6 and 8-cylinders have more power strokes than
does the 4-cylinder.
B) The 6 and 8- cylinders have more compression strokes
than does the 4-cylinder.
C) There are 1, 2 and 3 power strokes for the 4, 6 and
8-cylinders respectively.
D) It means the number of times the piston goes in and
out of a cylinder.
Teacher 38
Lecture 19
Driving down the highway you
notice that when you roll down the window in the front, your ears pop. The pressure in the car has
changed. This occurs because
a. Air bending toward the
car has low pressure causing a flow of air out of the window.
b. Air bending toward the
car has high pressure causing a flow of into the car.
c. Air bending away from the
car has low pressure causing a flow of air out of the car.
d. Air bending away from the
car has high pressure causing a flow of air into the car.
Lecture 20
Now that I know about spin
and its effect on golf balls, I should be able to understand my swing a little
better. Why?
a. The more backspin on the
ball, the greater the upward lift and a higher trajectory.
b. The more backspin on the
ball, the greater the Magnus force and a higher trajectory.
c. The more backspin on the
ball, the greater the wake deflection force and a higher trajectory.
d. The more backspin on the
ball, the less upward force and a decrease in trajectory.
Lecture 21
In the Wright Flyer
competition for Science Olympiad students build model planes and are judged by
how long the plane stays in the air.
The best models rise quickly and circle downward during their descent. What is one feature that students can
do that may help a plane achieve this?
a. Increased the angle of
attack of the wings.
b. Build wings that have
symmetrical airfoils.
c. Decrease the angle of
attack of the wings.
d. Build a glider that
doesnÕt have a propeller.
Lecture 22
In the movie Apollo 13 that
we saw in class, the crew used rocket propulsion to straighten their ship and
get it on the correct trajectory toward earth. Rockets are ideal for space flight because they
a. Use gas to provide the
thrust and donÕt grab air to give them forward thrust.
b. Get lighter as they burn
fuel so they donÕt need as much thrust to gain forward momentum.
c. Burn huge amounts of
fuel-air mix to give them a large amount of forward momentum.
d. Compared to other
propulsion devices, they donÕt need as much air to propel them forward.
Lecture 23
Take a look next time you
fly to grandmaÕs house youÕll notice the huge fans (turbofans) at the front of
the engine. These fans help the
plane to be more efficient by regulating amount of air pushed back through the
fans. How does changing the amount
of air through the fans help with efficiency?
a. Increasing the amount of
air decreases energy lost by the plane to the air.
b. Decreasing the amount of
the air decreases the speed and the amount of energy loss.
c. Increasing the amount of
air increases the speed of the plane, less fuel is used.
d. Decreasing the amount of
air decreases the lift off speed and less fuel is used.
Lecture 24
Which of the following
statements is true about heat?
a. Heat is the transfer of
thermal energy.
b. Heat is the amount of
kinetic energy in a substance.
c. Heat is the amount of
chemical potential energy in a substance.
d. Heat flows naturally from
a low temperature to a high temperature.
Lecture 25
In mid-July, your air
conditioner breaks. You need to
find a comfortable place to sleep. Thanks to physics, you know exactly were to
go. WhereÕs the best place to
sleep?
a. In the basement, the
cooler air is denser and will therefore settle in the basement.
b. In the basement, the
cooler air is less dense and will therefore settle there.
c. In the basement, the
cooler air is less dense, the buoyant force is low & air will sink.
d. Anywhere in the house
because the cooler air will circulate due to convection currents.
Lecture 26
A great campfire food is the
sÕmore. In order to make a great
sÕmore, the marshmallow isnÕt burnt and is a golden brown. WhereÕs the best
place to roast the marshmallow?
a. On the coals Ð radiation
will heat marshmallow evenly and not burn it.
b. Above the fire -
convection will heat the marshmallow evenly and it wonÕt catch on fire.
c. On the sides of the fire
Ð radiation will cook the marshmallow evenly.
d. The middle of the fire -
conduction and convection will cook the marshmallow evenly.
Lecture 27
Your best friend is on his
environmental kick and tells you your high lumen light is wasting
electricity. You tell your
misguided friend that he is wrong.
Why are these lights more efficient than low lumen lights?
a. Most of the thermal
radiation comes off as visible light, not infrared light.
b. Most of the thermal
radiation comes off as infrared radiation and is more efficient.
c. They radiate only a small
amount of thermal energy and most of it is not lost as heat.
d. They burn at lower
temperatures therefore it takes less energy to see the visible light.
Lecture 28
Which of the following would
cause an inefficient light bulb?
a. A bulb that burns at low
temperatures.
b. A filament that has an
increased surface area.
c. A gas in the bulb that is
reactive with tungsten atoms.
d. A filament that sublimes
at high temperatures.
Lecture 29
For a summer job you agree
to mow your neighborÕs yard once a week.
In order to cool off, you go over to the AC as the fan is blowing. To
your dismay, itÕs blowing hot air! The air blowing out from the AC fan is hot
in order to
a. Increase the amount of
entropy outside and move heat against its natural flow
b. Increase the amount of
entropy inside and move heat against its natural flow.
c. Decrease the amount of
entropy outside and move heat against its natural flow.
d. Keep the entropy the same
inside & outside and move heat against its natural flow.
Lecture 30
When I was little I had a
cat named Cleo. During the winter months, her favorite place to cat nap was
behind the refrigerator. Explain
why this spot was her favorite place to sleep.
a. The fridge takes heat
away from the food and deposits this heat in the back.
b. The fridge puts moisture
into the food and deposits heat in the back.
c. The fridge takes coldness
out of the air and deposits the cool air into the fridge.
d. The fridge takes moisture
out of the food deposits this warm, moist air in back.
Lecture 31
The temperature of a gas
increases when it is squeezed during the compression stroke of a four-stroke
engine. This is because:
a. The piston does work on
gas, energy is transferred to gas and gas gets hotter.
b. The piston does work on
gas and friction increases between the molecules.
c. The gas does work on
piston, gets energy from the work and gets hotter.
d. Pressure increases, the
gas molecules move into a smaller space and get hotter.
Lecture 32
Which of the following does
not contribute to the efficiency of a gasoline car engine?
a. Burning most of the gas
in the cylinder.
b. Compressing as much
fuel-air mix into the cylinder without knocking.
c. Increasing the
temperature of the fuel-air mix as much as possible.
d. Limiting the amount of
energy used during the induction, compression and exhaust strokes.
Lecture 33
One hot summer day, you put
your water bottle filled with water (of course!) into the freezer. You came back the next day and notice
the bottle exploded. Why is ice
able to expand when it freezes and float in liquid water?
a. Molecules in ice are not
arranged as compactly as they are liquid so the ice floats.
b. Molecules in ice are
arranged more compactly than in liquid so the ice floats.
c. Ice crystals have less
mass than liquid water and therefore ice floats.
d. Molecules in ice vibrate
quickly and therefore are less compacted than in liquid.
Teacher 39
Lecture 27
will
reach temperatures close to 7000 C, we will see the emitted lightÉ
Lecture 28
Lecture
29
Lecture
30
Lecture
31
Lecture 32
11. In Dr.BloomfieldÕs demo of fuel burning
in an engine he was able to get detonation
becauseÉ
a. fuel air mixture did not light evenly moving from
bottom of jug to top
b. fuel and air mixture was already heated before charge
was passed through it
c. fuel and air mixture lit evenly
at first then speedup due to pressure
d. fuel and air
mixture spontaneously combusted
Lecture
33
each phase change to beÉ
Teacher
40
Teacher 41
1. The reason that foam
material can be successfully used as thermal insulation is because
(a) Air trapped in the foam
is a poor conductor of heat from the warm to the cold side.
(b) Air trapped in the foam
is a poor radiator of heat from the warm side to the cold side.
( c) The foam is usually not
a good conductor because electrons are not free to move.
(d) Trapped air will reflect
all thermal energy back to its source.
2. A light bulb is turned on
and it appears to be glowing redder than a second light bulb that appears to be
glowing yellow. What can be said of the red light bulb compared to the yellow?
(a) The red glowing filament
is cooler and emitting light with less energy than the yellow.
(b) The red glowing filament
is hotter and emitting light with more energy than the yellow.
( c) The red glowing
filament is cooler and emitting light with more energy.
(d) The red glowing filament
is hotter and emitting light with less energy than the yellow.
3. Which teapot will keep
tea hotter for a longer period of time, a flat black pot or a shiny silver pot?
(a) The shiny silver teapot
because it is a poor absorber and emitter of energy.
(b) The shiny silver teapot
because it is a good absorber and good emitter of energy.
(c ) The black tea pot
because it is a good absorber and emitter of energy.
(d) The black tea pot
because it is poor absorber and emitter of energy.
4. The process that is the
opposite of sublimation.
(a) Frost formation.
(b) Boiling.
(c ) Evaporation.
(d) Melting.
5. Which of the following is
the principle process employed when broiling a steak in your home oven?
(a) Thermal Radiation.
(b) Thermal Conduction.
( c) Thermal convection.
(d) Thermal
Sublimation.
6. Following a winter
snowstorm, on which driveway will water more likely appear first?
(a) A black top driveway
because black is a good absorber of energy.
(b) A cement driveway
because cement is a good conductor of energy.
(c ) A stone driveway because the stones
have more surface area for absorption.
(d) A dirt driveway because
the snow will be absorbed by the dirt.
7. Why would a camper wrap
his canteen in a wet cloth?
(a) As the fluid in the wet
cloth evaporates, it will keep the canteen cool.
(b) The wet cloth will
ensure that water vapor will condense on the cloth making it cooler.
( c) Water in the cloth will
resist any temperature changes.
(d) The water molecules in
the cloth are polar and hold more energy.
8. If the energy of a
thermally isolated system never decreases, what is essential for an air conditioner
to work?
(a) Ordered energy in the
form of electricity is converted into thermal energy.
(b) An evaporator must be
located outside of the house.
( c) A condenser must be
located inside the house.
(d) A working fluid must
remain a liquid at all times.
9. An air conditioner is an
example of
(a) A heat pump moving heat
against it natural flow.
(b) A heat engine by
creating work as the heat flows.
( c) A heat pump assisting
heat to move with its natural flow.
(d) A heat engine using work
to move heat against its natural flow.
10. In a house that has a
damp basement, the homeowner may use a dehumidifier to remove the excess water
vapor. This is accomplished by
(a) Separating water from
the air with out a change in temperature.
(b) Cooling all of the air
in the basement so that water condenses into a pail.
( c) Heating the air in the
basement to dry it out.
(d) Capturing the water
vapor by allowing it to attach to the working fluid.
11. Heat engines work best
when
(a) The temperature
differences are greater.
(b) The temperature
differences are small.
( c) The temperatures are
the same.
(d) It is hotter at the end
than at the start.
12. Which strokes of the
internal combustion engine require the engine to do work?
(a) Induction, compression,
exhaust
(b) Induction, ignition,
exhaust
( c) Compression, induction,
ignition
(d) Compression, exhaust,
ignition
13. A high compression ratio in an internal
combustion engine
(a) May cause pre-ignition,
so a premium fuel is used.
(b) Eliminates pre-ignition,
so any fuel can be used
( c) Requires a premium fuel
because it contains more energy.
(d) Requires any fuel
because the energy content is the same.
14. An inter-cooler of a
turbo charger
(a) Cools the compressed air
before it enters the cylinder.
(b) Warm the compressed air
before it enters the cylinder.
( c) Compresses the air
before it enters the cylinder.
(d) Cools the exhaust before
it leaves the engine.
15. Diesel engines differ
from gasoline internal combustion engines in that the diesels
(a) Highly compress the air
prior to fuel being added.
(b) Compress fuel and air
together.
( c) Compress the fuel only.
(d) Uses a fuel that has a
high ignition temperature.