Question

Stopping distance of a moving vehicle is directly proportional to

• A. square of the initial velocity.
• B. square of the initial acceleration.
• C. the initial velocity.
• D. the initial accleration.

Answer 1

The correct option is A square of the initial velocity.

Let $s$ be the distance travelled by the vehicle before it stops.
So, final velocity would be $v=0$, let say, initial velocity is $u$
Using equation of motion
$v^2-u^2=2as$
$\Rightarrow 0^2-u^2=2as$
So, stopping distance $s=-\frac{u^2}{2a}$
Thus, stopping distance is proportional to the square of the initial velocity.