A car of mass 1530 kg traveling at 27.0 m/s is at the foot of a hill that rises 115 m in 4.40 km. At the top of the hill, the speed of the car is 6.0 m/s. Find the average power delivered by the car's engine, neglecting any frictional losses

I got 8145.7 watts but that is not the correct answer.

2 answers

total energy at top
= (1/2)(1530)(36) + 1530(9.81)(115)

total energy at bottom
= (1/2)(1530)(27)^2

work done = energy at top - energy at bottom

average velocity = (27+6)/2
time = 4400/average velocity

power = work done/time
the difference in total energy (kinetic plus potential) at the base and the top; is the energy input from the engine

the ascent time is the average speed, (top + bottom) / 2; divided by the 4.40 km distance

energy / time equals power

your answer has 5 sig figs. but all the data is only 3