Question

A 1550 kg car is initially at rest on level ground when the engine does 450 000 J of work on it. If all of the work is converted into kinetic energy, what is the final speed of the car?

Answer 1

24.1 m/s

Step-by-step explanation:

Work = change in KE =
`KE_(f) - KE_(i)`

KE initial is 0 because the initial velocity is 0. Therefore, work is equal to final kinetic energy. With that:

`W = KE_(f) = (1)/(2)mv_(f)^(2)`

With some algebraic manipulations,

`v_(f) = \sqrt{(2W)/(m) } = \sqrt{(2*450000 J)/(1550 kg) } = 24.1 m/s`