As a result of doing work, a person supplies a machine with 1100 J of energy in 12 seconds. The machine in turn does work and delivers 900 J of energy in 14 seconds to some object. What is the efficiency of this machine?

Answer 1

I answered this yesterday. Check previous drwls answers using the search box in the upper right.

Are you the same person who asked it before or is this from nationwide assignment of some online or or home schooling course?

Repeat posts are an annoyance here.

Answer 2

http://www.jiskha.com/display.cgi?id=1264363964