Buoyant Force
We all know that we feel lighter in a pool. Clearly the water exerts a force on us,
opposing gravity. And it does so to all objects. All fluids in fact (even the atmosphere)
exert a buoyant force on objects submerged or partially submerged i
Fluids
Were now going to switch from a study of objects moving under the influence of forces,
to a study of fluids moving under the influence of forces, or rather pressures. We will do
this the same way weve analyzed everything so far with Newtons second
Field due to continuous mass distributions
If we have a continuous distribution of masses, then our sum is modified to an integral,
Example
Consider a long straight mass wire with a constant mass per unit length . And lets
calculate the field at a distanc
Derivation of Keplers laws (well two of them anyway)
Now well examine the motion of planets, satellites about the Sun. Specifically, lets
look at Keplers three laws,
From his law of gravitational attraction between two spherical masses, Newton was able
to
Gravitational field near the Earths surface
What is the gravitational field of the Earth, near its surface?
Well, it is
That is, it is just the acceleration due to gravity. This isnt a coincidence. The
gravitational field at a point gives the acceleration
Gravitational force due to the two spherical masses
Consider again the two spherical charges examined above, illustrated below,
where the magnitude and direction of the field was found to be:
Now heres the question. If we place a mass (m = 12kg) at the po
Vacuum Cleaners
Vacuum cleaners use the principles weve been talking about. Consider the following
diagram,
When you plug in the vacuum cleaner, the electric current operates the motor. The motor
is attached to the fan, which has angled blades, like an ai
What is the maximum length of pipe, , that can be used in this manner to draw water
from a reservoir?
Well (no pun intended), if you can evacuate all the air from the pipe, as aforementioned,
then the pressure at the top of the pipe will be P = 0. The pre
Gravitation
Now weve pretty well covered the dynamics of objects. Wed like to apply all of this to
the question which started this line of inquiry over 300 years ago. That question is: what
path do the planets follow, and what causes the planets to move t
Gravitational Force
So far weve spent a lot of time talking about the gravitational field set up by a mass.
Now wed like to examine what force the gravitational field exerts on an object placed
next to that mass. Consider an analogy. As aforementioned, a