Question

A 980 kg car uses a braking force of 9600 N to stop in 1 seconds.

(a) What impulse acts on the car?

(b) What is the change in momentum of the car?

(c) What was the initial speed of the car? (Use only two decimal places.)

Answer 1

(a). Impulse = (force) x (time) = (9,600 N ) x (1 sec) = 9,600 N-sec

(b). change in momentum = impulse delivered = 9,600 N-sec = 9,600 kg-m/s

(c). The car's initial momentum was 9,600 kg-m/s .

Momentum = (mass) x (speed)

9,600 kg-m/s = (980 kg) x (initial speed)

initial Speed = (9,600 kg-m/s) / (980 kg)

initial Speed = 9.79 m/s