1. The problem statement, all variables and given/known data Calculate the force that the man (weight 70 kg) should exert on the rope to stay in balance. (answer = 137,2 N) [PLAIN]http://img651.imageshack.us/img651/7682/oefkoen.png [Broken] 2. Relevant equations Like I see, there are two ropes who are in equilibrium. In each rope the tension is the same but different from each other. I suppose the sum of the tensions of both ropes are equally to the weight of the person 3. The attempt at a solution The netforce is zero cause there's no movement or acceleration Rope 1 = the rope who holds the chair. Rope 2 = the rope the man holds. in positive y-direction : T(rope1)-mg/2=0 (/2 because the weight from the two ropes are from the same person) so T(rope1)=mg/2 the other one T(rope2)=mg/2 like you see my equations doesn't match the answer. I know that the rope 2 depends on rope 1 cause they are attached to each other. But i can't write that mathematical equation. Can you help me?