Physical Science
posted by Leah .
When you do 100 J of work on the handle of a bicycle pump, the pump does 40 J of work pushing the air into the tire. What is the efficiency of the pump?

MIND YA BUSINESS .

Efficiency is "Efficiency = (useful work output / work input)"
So the problem would look like:
EC = (40/100)
Divide 40 by 100, and you get 0.4  which is 40%. 
A river does 6,500 J of work on a water wheel every
second. The wheelâ€™s efficiency is 12%.
a. How much work in joules can the axle of the
wheel do?
b. What is the power output of the wheel in 1 s?