1. Consider an automobile with a mass of 5,750 lbm braking to a stop from a speed of 60 mph.

a. How much energy (in BTU) is dissipated as heat by friction during the braking process?

b. Suppose that the automobile could be equipped with a battery and energy recovery system which could capture 48% of the braking energy. If the car has a 12-gallon tank and a fuel economy rating of 35 miles per gallon, how many additional miles could be travelled on a single tank if the energy recovery system was installed? Note: Assume 200 braking events occur on a single tank of gasoline.

Answers:

Part A: -890 BTU

Part B: 26 miles