A block is at rest on a horizontal surface with coefficients of friction and

PHYSICS · Subjective · CBSE · Physics · Laws of Motion · Laws of Motion

Problem

3\,\text{kg}

block is at rest on a horizontal surface with coefficients of friction

\mu_s = 0.40

and

\mu_k = 0.30

. A horizontal force that increases uniformly with time at the rate

6\,\text{N\,s}^{-1}

starts acting on the block at

t = 0

. (i) Calculate the instant when the block starts sliding. (ii) Find the speed of the block

4\,\text{s}

after sliding begins, assuming the force continues to increase at the same rate.