What is the average force required to pull the rope?

[geoffrey159]

There are way too many averages in this problem, it goes beyond my understanding.
Many thanks for your help Haruspex, Orodruin, Bvu , I think you've done everything possible to make me understand, but it is not possible.
I give up for now, maybe once I know energy I'll have another perspective on this problem. Thanks again!

 

[NascentOxygen]

There are way too many averages in this problem, it goes beyond my understanding.
Many thanks for your help Haruspex, Orodruin, Bvu , I think you've done everything possible to make me understand, but it is not possible.
I give up for now, maybe once I know energy I'll have another perspective on this problem. Thanks again!

I think for half marks you should just work out the force needed to transport the string of skiers up the slope, neglecting the extra force involved in initially bringing each up to speed. The problem neatly breaks apart into two parts, so if you complete one you should be eligible for half the marks.
Good luck with your studies! http://thumbnails112.imagebam.com/37333/0363e9373324851.jpg