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A car of mass m is driven with accelera...

A car of mass m is driven with acceleration 'a' along a staright level road against a constant external resistive force R' . When velocity of car is v , the rate at which the engine of car is doing work will be `...........`

A

Rv

B

mav

C

`(R+ma)v`

D

`(ma-R)v`

Text Solution

Verified by Experts

The correct Answer is:
C
Power of car is the rate at which the car can do the work .If necessary force F for constant velocity , then
P = Fv
Force required to oppose resistive forcce R and move with acceleration a is F , then
F = ma
` :. ` Power `P = Rv + Fv`
` = (R+F) v`
`= (R+ma)v`
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