Physics
posted by Leah .
The mass of a car is 2400 kg. the constant power supplied by the engine is 60 kW and the car starts from rest. What is the speed of the car at the end of 2 seconds?

derp 10 m/s

17m/s

We know the power (6x10^4 Watts), and that power equals work over time. If you solve for the work, you get 1.2x10^5 Joules. Work is a form of energy, and if you set the initial kenetic energy (0 joules) plus the work done by the engine equal to the final kenetic energy you can solve for the final velocity.