Answer:
Friction is a force tends to oppose relative motion between bodies when they are in direct contact. Remember this friction does not oppose motion, it opposes relative motion.
Explanation:
The velocity of the car at the bottom of the hill=19.8 m/s
mass= 100 kg
height= h=20 m
Velocity at the bottom=V
Using the law of conservation of energy
potential energy at top = kinetic energy at the bottom
m g h= 1/2 m v²
g h= 1/2 v²
9.8 (20)=1/2 V²
V=19.8 m/s
Thus the velocity of car at the bottom of hill=19.8 m/s
