A 1,200 kg car rolls down a hill with its brakes off and transmission in neutral. At one moment it is moving 5.0 m/s. A little later it is moving at 8.2 m/s. How much did its height change between the two times? Assume friction and air resistance have no effect on its motion.
The change in kinetic energy of the car is equivalent to the change in its potential energy. Thus: K.E = P.E 1/2 x mΔv² = mgΔh h = (8.2² - 5²) / 2(9.81) h = 2.15 meters
