Remember Sten? His mass is 70 kg, the bench is 10 kg.He's pulling on the rope with a force F, slowly and steadily lifting himself and the bench. What size force does he need to exert, to keep himself moving up? Please find your answer two ways, and compare. 

a) First way: Review and explain the reasoning I offered in my solutions. Don't just quote me; explain in your own terms. 

b) Second way, based on work and energy, in three steps. Step 1: Suppose Sten pulls 1 meter of rope through his hands, which makes his seat move up. How far up, Δh, does the bench move? 

c) Step 2: What is gain in gravitational potential energy, when Sten and the bench move up that distance Δh?

d) Step 3: What size force does Sten exert on the rope, to do that much work? Does this answer agree with the first way you did it, in part a?

Answer rating: 100% (QA)

lets solve the problem using both approaches a First Way Review of the reasoning In the first approa... View the full answer