Question

a body is acted upon by a force . state two conditions when the work done is zero.

Answer 1

1. When there is no force or no displacement.. or the direction of displacement is perpendicular to the direction of force then the work done is zero.
2.When the displacement is zero OR when the force acts at right angles to the direction of the displacement then the work done is zero.

Answer 2

Two conditions when the work done is zero:

• When there is no displacement in the body i.e, s=0. Here the force which is acting on the body must get canceled out by some other forces like friction so that the displacement is zero.
• When the force acting on the body is right-angled with the direction of displacement of the body. Here if the body is in the horizontal plane then the applied force is getting canceled out by the normal force.