A car (mass = 860 kg) is at rest on the top of a tall hill. the car rolls down the hill and at the bottom, reaches a top speed of 19 m/s.

A) find the force of gravity on the car
560 x 9.8 = 5488 N
B) find the work done by gravity on the car
W = change in energy = kinetic energy
k= .5(560)(19^2) = 101,080 J
C) find the maximum height of the hill
Potential Gravity = M G H
101,080 = (560)(9.8)H
H = 18.4 M
In reality, the height of the hill is 23 m tall.
d0 find the % of total energy that was lost due to friction
I am so lost on this part.