Question

An object has a gravitational potential energy of 24 joules when it rests on a shelf 3 m above the ground. what would be its gravitational potential energy when it is lowered to a shelf 1 m above the ground?

Answer 1

The equation for the gravitational potential energy Ep is:

Ep=m*g*h where m is the mass of the body, g=9.81 m/s² and h is the height of the body.

First we need to find the mass of the body:

m=Ep/(g*h)=24/(9.81*3)=0.82 kg

Now lets see what it's gravitational potential energy would be on the height of 1 m.

Ep=0.82*9.81*1 = 8 J

On the height of 1 m the body has a gravitational potential energy of Ep=8 J.