Question

While hammering a nail, you put in 30 Joules of work. The hammer then puts out 10 J of
work on the nail. What is that hammer's efficiency?

A. 300%

B. 40%

С. 33%

D. 33 J

Answer 1

Answer:

C    Don't worry if you thought it was D. I almost answered that.

Explanation:

Remark

You can get this just by learning the vocabulary.

Efficiency = Work Out / Work In * 100%

Work in = 30J      That's you swinging the hammer.

Work out = 10 J    That's how much of the hammer's work gets to the nail.

Efficiency = (10/30)*100

Efficiency = 1/3 * 100

Efficiency = 33%

Answer 2

Answer:

I think its 40%, pls correct me if I am wrong :(

Explanation: