derive an expression for the potential energy of an object of mass 'm' raised to height 'h'.

Consider an object of mass ,m. Let it be raised to point B through a height ,h from the ground . A force is required to raise the object is equal to the weight of the object ,mg. that is, F=mg.

The object gains energy equal to the work done on it . Let the work done on an object against gravity be W. That is :-

Work done, W =force * displacement

W =F *H

W =mg *H                  [ F=mg ]

W =mgh   ..............(1)

Since ,work done on an object is equal to mgh, an energy equal to mgh units is gained by an object. This is potential energy of the object & is denoted by Ep.Thus,

Ep =W    ...................(2)

from (1) &(2)

Ep = mgh

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P.E = mgh
(W= F×s , instead of F put mg, instead of s put h)
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