Physics
What is meant by gravitational potential energy? Derive an expression for it for a body placed at a height above the ground.
Answer
The potential energy possessed by a body due to the force of attraction of the earth on it, is called the gravitational potential energy.
When a body is placed at a height above the ground then the amount of work done in lifting the body to that height against the force of gravity is called the gravitational potential energy.
When we lift a body of mass m from the ground to a height h.Then, force of gravity (mg) acts on the body acting vertically downward which must be equal to the least upward force F required to lift the body.
Work done = force of gravity (mg) × displacement (h)
⇒ W = mgh
So, the work done on the body is stored in the form of its gravitational potential energy when it is at a height h.
Hence,
Gravitational potential energy U = mgh.
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