Question

When a car driver travelling at a speed of 10 m/s applies brakes and brings the car to rest in 20 s, then
the retardation will be

Answer 1

A car driver is traveling at a speed of 10m/s .

e.g., initial velocity , u = 10m/s

He applied break and brings to the car to rest in 20s.

so, time taken to stop the car = 20s

we have to find retardation.

final velocity of car , v = 0

use formula, v = u + at

0 = 10 + a20

a = -1/2 m/s²

Answer 2

Question :-

When a car driver travelling at a speed of 10 m/s applies brakes and brings the car to rest in 20 s, the retardation will be

Given :-

• u = 10 m/s

1. v = 0 m/s

• t = 20 s

To find :-

Retardation

Solution :-

Substituting the values in 1st equation of motion :-

v = u + at

0 = 20 + 20a

20a = -20

a = -1 m/s²

Retardation = 1 m/s²