Avg potential energy of molecules in a reservoir

[brainslush]

Homework Statement

An insulated cylindrical reservoir of height H is suspended vertically in the field of gravitation. Find the average potential energy of the molecules in the reservoir.

Homework Equations

F = [tex]\frac{Gm_{1}m_{2}}{r^{2}}[/tex]

The Attempt at a Solution

To be honnest I have no clue what to do! Could you please give me a slight hint.

There is no change of pressure, volume or temperature. Another thing is that most of the molecules will be located close to the Earth's surface but due to their movement you will have some kind of distribution.

 

[jbsteele]

The potential energy of a particle is given by its mass ($m$) times the acceleration due to gravity ($g$), multiplied by its height above a reference level:$U = mgh$So, the average potential energy of the molecules in the reservoir can be found by taking the sum of all the potential energies of the molecules multiplied by their respective probabilities of finding them at that height and dividing by the total number of molecules.