7. Assume that it takes a certain amount of energy, E, to cause a car to move at 25 miles/hour. a) In terms of E, how much energy will it take to make the car move at 50 mi/hr? 75 mi/hr? b) In 1978, the maximum speed allowed on the Maine Turnpike was reduced from 70 to 55 mi/hr as an energy conservation measure. What fraction of the energy used as 70 mi/hr was saved by this maneuver?

	Going fast in a car costs a lot of energy.
	If a lower speed limit means such a big savings in energy (and therefore $$$$,) then why is the speed limit higher now than in 1974