Question

A car travels with a uniform velocity of $25$ m/s for $5$ s. The brakes are then applied and the car is uniformly retarded and comes to rest in further $10$ s. Find the distance which the car travels before the brakes are applied.

Answer 1

Graphical representation of the problem:
Initially the car moves with uniform velocity of $25$ m/s for $5$ sec, then brakes are applied, and the car comes to rest after $10$ sec i.e., at t $=15$ sec.

Distance covered before applying brakes: Here car is moving with a uniform velocity, $u=25\text{m}/\text{s}$
So, distance travelled $\left(d\right)=ut$
(as acceleration is 0 )
$\Rightarrow d=25\text{m}/\text{s}\times 5\text{sec}=125\text{m}$

Hence, the distance covered by the car before brakes are applied is $125\text{m}$.