Question

A mass of 9.22 kg gains 506 J of gravitational potential energy. To what height was it lifted?

Answer 1

When you lift a box up off the floor, you must exert a force at least equal to the weight of the box. If you lift the box at constant speed, you "do work" on the box that would be equal to the force you exert (the weight of the box) times the height through which you lifted the box. If you exert a force of 50 Newtons on the box and lift it 1 meter high, then you did (50 N)x(1 m) or 50 N-m of work on the object. 1 Newton-meter is called a Joule (J), pronounced "jewel." In lifting the 50 N box upward 1 meter at constant speed, you would do 50 Joules of work on the box. That means your body used 50 J of energy to lift the box.