Question

A car travelling at a speed of 30km/h is brought to rest in a distance of 8m by applying brakes. If the same car is moved at a speed of 60km/h then it can be brought at rest with same brakes in

Answer 1

car race to apply brake in 58 kilometre

Answer 2

Answer:32 m

Explanation:Newton's motion equation:

v^2 = u^2 – 2as…….. where a: retardation (opposite of acceleration) and s: distance covered.

1st case:

u = 30 km/h = 25/3 m/s

v = 0,

s = 8 m

Therefore, 0^2 = (25/3)^2 - 2 × a × 8

This gives a = 4.34 m/s^2

2nd case:

u = 60 km/h = 50/3 m/s

v = 0

a = 4.34 m/s^2

Now, 0^2 = (50/3)^2 - 2 × 4.34 × s

This gives s = 32 m

Thus on applying brakes the car will stop after covering 32 m.