PHYS 231 Quiz #5

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		   		P=F/A

		If an equation you need is not listed here, ask.

Multiple choice: 1 pt. each

1. Which of the following exhibits simple harmonic motion?

A. A pendulum swinging with large amplitude.

* B. A mass attached to a spring.

C. A rubber ball bouncing on the ground.

D. All of the above.

2. A particle is exhibiting simple harmonic motion along the x axis about the origin. At a given point in time, the direction of its acceleration is in the -x direction. At this time, the displacement of the particle is

A. in the -x direction.

B. zero (at the origin).

* C. in the +x direction.

D. Not enough information is given.

3. A mass attached to a spring has a maximum speed of 10 m/s and a maximum acceleration of 20 m/s . The frequency of the spring's oscillations is

A. 2 Hz

B. .5 Hz

* C. .318 Hz

D. .0796 Hz

4. The motion of an oscillating mass is described by the equation . What is the period of the oscillations?

A. s

B. s

* C. s

D. s

5. Which of the following is NOT constant during simple harmonic motion?

A. amplitude

* B. potential energy

C. frequency

D. period

6. A particle exhibiting simple harmonic motion has a mass of 2 kg and an angular frequency of 5 rad/s. The total energy of the particle is

A. less than 20 J.

B. greater than 20 J.

C. not constant. There is no single answer.

* D. constant, but unknown. Not enough information is given.

7. Two objects are in thermal contact. Object 1 is at a higher temperature than object 2. Which of the following is true?

A. Objects 1 and 2 are not in thermal equilibrium.

B. Heat is transfered from 1 to 2.

* C. Both A and B.

D. Neither A nor B.

8. A woman switches from high heels to flats (shoes with wider heels). What happens?

A. The force of her heels on the ground increases.

B. The pressure of her heels on the ground increases.

C. The force of her heels on the ground decreases.

* D. The pressure of her heels on the ground decreases.

9. At time t=0, a pendulum is released from an angular displacement of .1 rad. The length of the pendulum is 1 m. What is the equation for the angular displacement of the pendulum as a function of time? What is the maximum angular acceleration of the pendulum? (2 pts.)

a) A=.1 rad

(because displacement is zero when t=0)

b)

X-tra Credit (1 pt.): Why is it possible to lie down on a bed of nails?

When the force of the person's weight is distributed of the area of all the points of the nails, the pressure (P=F/A) is low enough for the person's skin to resist getting punctured.