Power

__//Problems//__
What would require more power: using only 22W bulbs to light up a room for 8.5 hours, or only using the room for 3.1 hours and lighting it with the same amount of 80W bulbs.

Sometimes you don't need all of the lights on. Often in class Miss Peterka will leave the middle row of lights off. This ultimately will save money on the power bill. Estimate how much power you think is being saved by turning off this one section of lights.

If you are ever next door in Mr. Mont's room you may not realize it right away, but he usually has two lights off in his room. How much power do you think he saves?

When an automobile moves with constant velocity, the power developed is used to overcome the frictional forces exerted by air and road. If the power developed in an engine is 55.0 hp, what total frictional force acts on the car at 23.9 m/s? (Hint: Note that one horsepower, 1 hp, is equal to 746 W.)