Physics

Problem

A block of mass

4\,\text{kg}

is kept on a horizontal rough table. Beginning at

t = 0

, a horizontal force

F

acting on the block is increased uniformly from zero at the constant rate

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

. The coefficients of friction between the block and the table are

\mu_s = 0.40

and

\mu_k = 0.30

. Take

g = 9.8\,\text{m s}^{-2}

. a. (i) Calculate the instant

t_0

at which the block just starts sliding. b. (ii) Determine the acceleration of the block at

t = 4\,\text{s}

. c. (iii) Find the distance travelled by the block in the first

6\,\text{s}

after the force began to act.