Question

list some examples in which no work is done on a body even through a force acts on it

Answer 1

1. we pushed the wall
2. if do written work
3.w hen two persons force equally on opposite sides of a box

Answer 2

Work done is calculated as a product of Force and displacement, i.e, W = Fs. So, it is important to have a certain force acting on an object which causes a displacement of the object through a particular distance. If either of the quantities is not present, it cannot be defined as work done.

Examples of situations where work done is zero, although a force is acting is - 

1. Standing still with a load on the head. - There is no displacement or movement although the heavy load may put force on the head or on the body.

2. Pushing an anchored tree, or a wall, are other examples, where futile efforts are put by applying force against an object which does not move or have a displacement.