Question

A car is moving on a straight road with some speed. The driver applies brakes so that car comes to rest with a retardation of $5m/s^2$ . The distance traversed by the car in last second of its motion is :

• A. $15m$
• B. $5m$
• C. $2.5m$
• D. $3.5m$

Answer 1

The correct option is B $5m$

During the last second acceleration is $-5m/s^2$ and car's final velocity is zero.

Thus, from the equation,

$u=v-at$

$u=0-\left(-5\right)\times 1$

$u=5m/s$

The initial speed of the car at the start of last second is $5m/s$ and after one second it stops.

Therefore, the distance covered in last second will be $5m$.