A moving car encounters air resistance which is proportional to the square of the speed of the car.What is the ratio of the power required at 40 km/hr to that required at 80 km/hrwith the same braking force?

The expression for power in terms of force and velocity:


But, it is given that F α v2

Hence, P α v3

Ratio of power:

P1P2=v1v23        =40803        =18

  • 18
What are you looking for?