*Michael Fowler 3/29/07*

**Pressure**:
standard unit Newtons/sq. m., or Pascals. (Also lbs/sq. inch, mm Hg.)

Pressure acts in all directions, normal to any surface immersed in fluid.

**Pascal’s Principle**:
in a static connected fluid, pressure same at points at same depth. Be able to
find the pressure as a function of depth in an incompressible fluid.

**Archimedes Principle:
**a body immersed, or partially immersed, in a fluid is thereby acted on by
an upward force of buoyancy equal to the weight of fluid displaced.

(Be able to explain the “ghost submarine” argument establishing this Principle.)

Use of Archimedes principle to find *density *of an object. Applications to ships, hot
air and helium balloons, etc.

**The Atmosphere**:
understanding the barometer, suction, etc. Know atmospheric pressure is about 10^{5}
Pascals.

**Boyle’s Law**: *PV*
= constant *at constant temperature*. Be able to use this to derive the

**Law of Atmospheres**: _{} and given the density
of air at STP be able to find *C*.

**Bernoulli’s Equation**:
_{} Be able to derive it,
and use it.

**Viscosity**:
understand the concept of laminar flow.
Know the definition of the coefficient of viscosity, _{}, and be able to apply it to find the rate of working in an
axle bearing (as in lecture notes), given _{}and the physical parameters of the system. Know the shape of the velocity profile for
steady flow between two plates, and for a river (but you won’t be expected to
derive that result). Understand how the
velocity varies near the surface of the river.

**Dimensions**:
understand *M*, *L*, *T*, that they don’t depend on the units
used, and that they can be used to find how, for example, flow rate in a pipe or
river varies with radius and depth.

Use dimensions to find **Stokes’
Law**, _{} (apart from the
constant). Be able to use Stokes’ Law
for small spheres in a viscous fluid.

Know that for water at room temperature _{}* *=1mPa×s = 10^{-3} Pa×s,
for air _{}* *= 2´10^{-5 }Pa×s
approximately.

*Be able to use
dimensions to*:

derive the formula for inertial
drag, _{}

Know the formula for the Reynolds number, _{} and *understand its
interpretation as a ratio of inertial effects to viscous effects*.