PHYSICS · Subjective · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A wooden block rests on a rough horizontal table. A student first pushes it gently with a small horizontal force and notices that the block does not move. She then pushes harder until the block is just about to slide, yet it is still at rest.
(i) Explain, with the help of appropriate reasoning, how the frictional force acting on the block changes as the applied force increases from zero up to its maximum limiting value.
(ii) Draw a clear free-body diagram of the block in the situation when it is just about to move, labelling all forces.
(iii) Distinguish between static friction and kinetic friction in terms of their behaviour and typical magnitudes for the same pair of surfaces.