Question

You are using a constant force to speed up a toy car from an initial speed of 6.5 m/s

to a final speed of 22.9 m/s. If the toy car has a mass of 340 g, what is the work
needed to speed this car up?

Answer 1

By the work-energy theorem, the total work done on the car is equal to the change in its kinetic energy:

W = ∆K

W = 1/2 (0.34 kg) (22.9 m/s)² - 1/2 (0.34 kg) (6.5 m/s)²

W ≈ 82 J