I NEED PHYSICS HELP???..it's about power that cars deliver?

Question

A car of mass 1470 kg traveling at 20 m/s is at the foot of a hill that rises 105 m in 3 km. At the top of the hill, the speed of the car is 14 m/s. Find the average power delivered by the car's engine, neglecting any frictional losses.

Answer 1

there are two factors.

The potential energy to raise the 1470 kg or 14400 N car 105 meters is J = 1510000

Additional kinetic energy is in the speed difference, 20-14 = 7

KE = ½mV²

KE = ½1470*7² = 36000J

energy total is the sum of the two,

1510000 + 36000 = 1550000 J

time do do this we have to calculate

Average speed is (20+14)/2 = 17 m/s

distance traveled is 3km (actually a bit more, but I'll skip that)

time is 3000 m / 17 m/s = 176 seconds

power is joules/sec = 1550000J/176 = 8800 watts or 12 HP