A motor-car of mass is travelling on a level

PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion

Problem

A motor-car of mass

1000\,\text{kg}

is travelling on a level, rough road at

20\,\text{m\,s}^{-1}

when the driver suddenly applies the brakes so that the wheels lock and the tyres slide. (i) Derive an expression for the stopping distance

s

of the car in terms of the initial speed

v_0

, the coefficient of kinetic friction

\mu_k

between tyres and road, and

g

. (ii) If

\mu_k = 0.30

, calculate the distance in which the car comes to rest and also find the total work done by friction during this process.