Question

Breaks applied to a car produce a uniform reterdection of 90cm/s.If the car was travelling with a velocity of 25m/s,then what distance will it cover before coming to rest.

Answer 1

a=90cm/s=-0.9m/s(as it is retarding)

u= initial velocity=25m/s

v=final velocity =0

by the third equation of motion we know=v^2=u^2=2as

0=25^2=2*-0.9*s

-625=-1.8s

-625/-1.8=s

s=347.222m=347 m approx