Average Power of a Car: How to Calculate and Understand It

[eshock202]

Homework Statement

mass of a car is 2000 kg that can go from 0-120 km/h in 3.5 seconds. What is the average power?

Homework Equations

I know that the average power is Work/time, or (force * displacement)/time = F*average velocity.

My only question is how to find the force of the car? is it just Mass*g?

The Attempt at a Solution

 

[Morphheus]

F=ma

In this case, the acceleration is not g, but something else.

If you consider the acceleration to be constant, you can easily determine the acceleration from the time and speed given in the initial conditions

 

[Redbelly98]

It's probably easier to use the work-energy theorem, which relates the work done to the kinetic energy. Then you don't have to assume that the acceleration was constant.