A car of mass 1000 kg is moving at a speed pf 30 m/s. Brakes are applied to bring the car to rest. If the net retardation force is 5000 N, the car comes to stop after travelling d m in t s. Then

Given,

Final velocity, v=0

Initial velocity, u=30ms⁻¹

Force = mass x acceleration

F=ma

a=F/m=−5000/1000=−5ms⁻²

From the First equation of motion,

v=u+at

0=30+(−5t)

0=30−5t

5t=30

t=30/5

t=6

Hence, after 6sec the car will stop.

Stopping distance 

$\mathrm{s}=\frac{{\mathrm{v}}^2-{\mathrm{u}}^2}{2\mathrm{a}}=\frac{0^2-{30}^2}{2(-5)}=90\mathrm{m}$