Question

A car starting from rest accelerates at the rate $f$ through a distance ${\text{s}}_1$, and then decelerates at rate $\frac{f}{2}$ through a distance ${\text{s}}_2$ to come to rest. Then $\frac{s_1}{s_2}$ is

• A. $\frac{1}{2}$
• B. $\frac{1}{3}$
• C. $\frac{1}{4}$
• D. 2

Answer 1

The correct option is A $\frac{1}{2}$

Velocity of the car varies with diplacement as

$v^2=u^2+2ax$

For accelerating part,

$v^2=0^2+2f\times s_1$ ....(i)

For decelerating part,

$0^2=v^2+2(-0.5f)\times s_2$ ...(ii)

From (i) and (ii)

$\frac{s_1}{s_2}=\frac{1}{2}$