Question

Starting from rest, a car of mass 1000kg accelerates steadily to 20m/s in 10s. The average power developed in the time period is:

a) 2000 W
b) 4000 W
c) 5000 W
d) 8000 W

Answer 1

The average power developed by the car is 4000 W.

Step-by-step explanation:

To find the average power developed by a car, we can use the equation:

Power = (work done) / (time)

First, let's calculate the work done by the car:

Work = (force) x (distance)

The force exerted by the car can be calculated using Newton's second law:

Force = (mass) x (acceleration)

Finally, the acceleration can be found using the equation:

Acceleration = (final velocity - initial velocity) / (time)

Plugging in the given values, we find:

Acceleration = (20 m/s - 0 m/s) / (10 s) = 2 m/s²

Force = (1000 kg) x (2 m/s²) = 2000 N

Work = (2000 N) x (20 m) = 40000 J

Finally, the average power can be calculated:

Power = (40000 J) / (10 s) = 4000 W

Therefore, the average power developed by the car is 4000 W. So the correct answer is b) 4000 W.