Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it.
- How much work is done by the men in lifting the box?
- How much work do they do in just holding it?
- Why do they get tired while holding it? (g = 10 ms-2)
- Zero, as the box does not move at all while holding it.
- In order to hold the box, men are applying a force which is opposite and equal to the gravitational force acting on the box. While applying the force, muscular effort is involved. So, they feel tired.