HELP for finals PLEASE!!! Can someone please quickly tell me how to determine the efficiency of this stupid pulley? I'm so lost at how to do it and finals are next week. Our set of books for our Principles of Technology class have to stay in the room and my teacher is grading the binder that has all my work in it! :grumpy: I've done most of the review on my own but I'm lost at what to do in these word problems... HELP! :surprised Here it is... Email me if you can... Crystal Find the efficiency of a pulley system that requires 30 Nm of work to life a 5kg box to a height of 3 m. I don't have to have the answer... If someone could post an example that would be great but I really just need to know the formula of how to do it. I'll post more as I need help... Thanks so much!!!!