Discussion Forum

A car of mass 1200kg (together with the driver) is moving with a constant acceleration of 2 m/s². 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)

Answer:

Explanation:

Power  of engine overcomes friction and provides necessary acceleration to the car

 Now friction, $f=\mu mg=0.5 \times 1200 \times 10$=6000 N

 and accelerating  force, F=ma=$1200 \times 2$=2400N

 So, total force produced by engine

  =$F_{r}$=8400 N

We know that, the formula pf power is 

 $P= F_{r}v$

 Then, $ 8400 \times 20 =168000 W $