1. The problem statement, all variables and given/known data In this figure, the man and the platform together weigh 950N. The pulley can be modeled as frictionless. Determine how hard the man has to pull on the rope to lift himself steadily upward above the ground. (Or is it impossible? If so, explain why.) http://www.webassign.net/serpop/p4-33.gif 2. Relevant equations 3. The attempt at a solution My thoughts: a) If there's a 950N force initially downward and he pulls upward (say 475N), wouldn't the tension in the string still be equal to 950N? In this case, wouldn't the man be pulling upward 475N plus an extra 475N? = impossible. b) The tension in each string equals the total tension in the system (is this true by the way?), so each string would have a tension of 950/2 = 475N, which is how much the man would have to pull upward. = possible.