A car of mass 1200 kg (together with the driver) is moving with a constant acceleration of 2 `m//s^(2)`. How much power does the engine generate at the instance, when the speed reaches 20 m/s? (Assume that the coefficient of friction between the car and the road is 0.5).

Options

A. 48000 W
B. 120000 W
C. 168000 W
D. 288000 W

Answer

C

Explanation

Power of engine overcomes friction and provides necessary acceleration to the car.
Now friction,`f = mu` mg `= 0.5 xx 1200xx10 =` 6000 N and accelerating force, F `= ma = 1200 xx 2 =` 2400 N
So, total force produced by engine `=F_(T)=8400` N
We know that, the formula of power is
`P=F_(T)v`
Then, P `8400 xx 20 = 168000` W