Question

13.
A car travels with a uniform velocity of 25 ms
for 5 s. The brakes are then applied and the car
is uniformly retarded and comes to rest in
further 10 s. Find : (i) the distance which the
car travels before the brakes are applied, (ii) the
retardation, and (iii) the distance travelled by
the car after applying the brakes.​

Answer 1

I. See the car travels at the speed of 25 m/s for 5 sec, So the distance travelled by car in 5 seconds must be 125m.

II. Retardation or acceleration's formula is

$a = \frac{v - u}{t}$

So, Retardation must be:

${2.5ms}^{2}$

III. See the formula for this is:

$s = \frac{ {v}^{2} - {u}^{2} }{2a}$

So, Distance travelled after applying brakes must be 125m.

Hope you got it :)