Question

What is the momentum in kg.m/s of a 10 kg car travelling at (a) 5 m/s (b) 20 cm/s, and (c) 36 km/h ?

Answer 1

(a) 5 m/s
We know that:
Momentum = mass × velocity
                   = m × v
Here, mass, m = 10 kg
velocity, v = 5 m/s
Putting these values in the above formula, we get:
Momentum = 10 × 5 kg.m/s
                   = 50 kg.m/s
 
(b) 20 cm/s
We know that:
Momentum = mass × velocity
                   = m × v
Here, mass, m = 10 kg
velocity, v = 20 cm/s
v = 0.2 m/s
Putting these values in the above formula, we get:
Momentum = (10)(0.2) kg.m/s
                   = 2 kg.m/s

(c) 36 km/h
We know that:
Momentum = mass × velocity
                   = m × v
Here, mass, m = 10 kg
velocity, v = 36 km/h
= `36 xx 1000/3600`
= `36 xx 1000/3600`
= `36 xx 10/36`
= 10 m/s
Putting these values in the above formula, we get :
Momentum = 10 × 10 kg.m/s = 100 kg.m/s