Question

Brakes are applied to a truck to produce an acceleration of $–10m/s^2$ . If the truck takes $5s$ to stop after applying the brakes, the distance covered by the truck before coming to rest is $250m$.

• A. 200 m
• B. 125 m

Answer 1

The correct option is B

125 m

Here,
Final Velocity $v=0$
Accleration $a=-10m/s^2$
Time take to stop $t=5s$
Let, $u$ be the initial velocity.

Using $v=u+at$,
$0=u+(-10\times 5)$
$\Rightarrow u=50m/s$

Also, $v^2$ = $u^2+2as$$\dots$[$s$ is the distance travelled]
$\Rightarrow 0={50}^2-2\times 10\times s$
$\Rightarrow s=125m$

Therefore, the truck will stop after $125m$.