Question

13. A car is moving with a uniform velocity of 30 m
It is stopped in 2 s by applying a force of 1500 N
through its brakes. Calculate : (a) the change in momentum of car, (b) the retardation produced in car, and (c) the mass of the car.
​

Answer 1

Answer:

-3000 kg m/s, -15 m/s², 100 kg

Explanation:

b. Retardation produced in the car

a = (v - u)/t

= (0 m/s - 30 m/s) / (2 s)

= - 15 m/s²

c. Mass of car

Force = ma

m = F/a

= - 1500 N / (- 15 m/s²)

= 100 kg

a. Change in momentum

Momentum = Mass × Velocity

Change in momentum = Mass × Change in velocity

= 100 kg (0 m/s² - 30 m/s)

= -3000 kg m/s²