A car of mass 1470 kg traveling at 22 m/s is at the foot of a hill that rises 140 m in 4 km. At the top of the hill, the speed of the car is 12 m/s. Find the average power delivered by the car's engine, neglecting any frictional losses.

Question

irishboy123 · Answer

first calc the **work** done by the car's engine over the climb.  that should EQUAL the change in **energy** of the car over the climb.  so compare energy at bottom with energy at top.  use the usual formulae for Kinetic and Potential Energy.

power measures work per unit time. 

 you do not have the time for the journey so i suspect that you will need to calc it dividing distance by speed where:
-  distance is about 4km though you could use Pytahgoreas and also add in the 140m vertical component
- speed: i would assume an average speed between the two speeds given at the bottom and top of the climb

divide work by time.