question_answer 30)

The sign of minus indicates that the work is being done against the moving car.  In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Answer:

(a) Here, the force acts at right angle to the displacement. So, work done by the force =0 (b) Here, the direction of displacement is the same as that of the force. So, work done by the force = + ve (c) Here, the body moves in a direction opposite to the direction of the force. So, work done by the force  = - ve