Question

What is the change of momentum of a car weighing 1500kg when its speed increase from 36km/hr to 72km/hr?

Answer 1

Hello Mate!

Since we know that,

p (momentum) = m(mass) × v(velocity)

In km/h, 36 km/h = 36 × 5/18 m/s or 10 m/s

Also, 72 km/h = 72 × 5/18 m/s or 20 m/s

Case 1

Initial momentum = 1500 kg × 10 m/s or 15000 kg m/s

Case 2

Final momentum = 1500 kg × 20 m/s or 30000 kg m/s

Change in momentum = Final p - Initial p

Change in momentum = ( 30000 - 15000 ) kg m/s

Change in momentum = 15000 kg m/s

Have great future ahead!

Answer 2

Heya !

Here's your answer !!

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Momentum = Mass × Velocity

GIVEN THAT :

Weigth of the car = 1500 kg

Initial velocity = 36 km/h

Since, the S.I. unit of momentum is kgm/s , we will change km/h into m/s

=> ( 36 × 1000 ) / ( 60 × 60 )

=> 10 m/s

Momentum ( p1 ) = 1500 × 10

=> 15000 kgm/s

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Final velocity = 72 km/h

Changing into m/s ,

=> ( 72 × 1000 )/( 60 × 60 )

=> 20 m/s

Momentum ( p2 ) = 1500 × 20

=> 30000 kgm/s

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Change in momentum = p2 - p1

=> 30000 - 15000

=> $\bf{15000 \: kgm/s }$

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Thanks !!