Question

A car moving with speed v on a straight track can
be stopped in a distance x by applying brakes. If
same car is moving with speed 2v and brakes
provide half the retardation then car will stop after
travelling distance
​

Answer 1

Answer:

8d

Explanation:

Assume retardation is a

initial velocity = v

final velocity = 0

by using formula, v^2=u^2+2as

0=v^2+2ad

v^2=2ad

a=v^2/2d  

so retardation in second case

a'=a/2

a'=v^2/4d

Now, use S=u^2/2a'

put value of a'

Here, u=2v

S=(2V)^2/2*V^2/4d

S=2*4d

S=8d