(A) The questions are based on the idea that the sign of work depends on the relative…
PHYSICS · Multi-part · CBSE · Physics · Work and Energy · Work and Energy
Problem
(A) The questions are based on the idea that the sign of work depends on the relative directions of force and displacement.
(i) Define mechanical work and state its SI unit.
(ii) For each situation given below, state whether the work done by the named force is positive, negative or zero. Give a brief reason in each case.
(a) A cyclist applies the brakes and the cycle comes to rest while moving forward.
(b) A donkey carries a sack of sand on its back and walks straight along a horizontal road.
(c) A boy hoists a flag upward on a vertical flag-pole.
(d) A box slides down a rough inclined plane under gravity.