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Question
What is the change in momentum of a car weighing 1500 kg when its speed increases from 36 km/h to 72 km/h uniformly ?
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Solution
We know that :
Momentum = mass × velocity
= m × v
Here, mass, m = 1500 kg
And, 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:
Initial Momentum = 1500 × 10 kg.m/s = 15000 kg.m/s
Also, we know that:
Momentum = mass × velocity
= m × v
Here, mass, m = 1500 kg
And, velocity, v = 72 km/h
= `72 xx 1000/3600`
= `72 xx 1000/3600`
= `72 xx 10/36`
= 20 m/s
Putting these values in the above formula, we get:
Final Momentum = 1500 × 20 kg.m/s = 30000 kg.m/s.
The change in momentum of a car weighing 1500 kg when its speed increases from 36 km/h to 72 km/h = 30000 kg.m/s − 15000 kg.m/s = 15000 kg.m/s.
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