Question

A car moving with a speed of $50km/h$, can be stopped by brakes after at least $6m$. If the same car is moving at a speed of $100km/h$, the minimum stopping distance is

• A. $6m$
• B. $18m$
• C. $24m$
• D. $2m$

Answer 1

Answer: (C)

$24m$

If final velocity is zero and acceleration is $-ve$ then.
$s=\frac{u^2}{2a}$

$s\propto u^2$

So, if the velocity is doubled than stopping distance will become $2^2=4$ $=6\times 4=24m$.