Question

A train moving with a velocity of $20m{s}^{-1}$ is brought to rest by applying brakes in $5s$. Find the retardation caused due to the brakes.

• A. $4m{s}^{-2}$
• B. $5m{s}^{-2}$
• C. $6m{s}^{-2}$
• D. $8m{s}^{-2}$

Answer 1

The correct option is A $4m{s}^{-2}$

$u=20m{s}^{-1}$
$v=0$
$t=5s$
Retardation, $a=\frac{u-v}{t}=\frac{20-0}{5}m{s}^{-2}=4m{s}^{-2}$