Question

Give one example each in which a force does
(a) positive work
(b) negative work, and
(c) zero work.

Answer 1

(a) When the body is displaced in the direction of the applied force, then the work is said to be positive work. Example: When a boy pushes a box forward by applying a force, the work done is positive.

(b) When a body is displaced in the opposite direction of the applied force, then the work done is said to be negative work. Example: When a boy takes a bag full of sand up to a height 'h', then the work done by the force of gravity is negative work.

(c) When the displacement of the body is zero then the work done by the applied on the object is said to be zero. Example: When a boy pushes a wall and the wall does not move, then the work done by the boy is zero.