**A 710kg car drives at a constant speed of 23m/s . It is subject to a drag force of 500 N. What power is required from the car’s engine to drive the car (a) on level ground?**

Answer:

The correct answer for A 710kg car drives at a constant speed of 23m/s . It is subject to a drag force of 500 N. What power is required from the car’s engine to drive the car (a) on level ground?

(a) 11500 W

The power required for the car’s engine is given by

P = Fv

where

F is the force that the engine must apply

v = 23 m/s is the velocity of the car

In this situation,the car is moving at constant velocity: this means that its acceleration is zero, so the net force on the car must be zero. Since there is a drag force of 500 N against the motion of the car, this means that the force applied by the engine in the forward direction must also be 500 N:

F = 500 N

So the power erogated by the engine is

P = (500 N)(23 m/s)= 11500 W