1. The problem statement, all variables and given/known data m(1) is 20kg m(2) is 30kg gravity use 10 U static is .6 u kinetic is .4 2. Relevant equations Basically my professor gave the answer to the question in the link along with the picture. The only problem is that i am not sure he did case three right and i am after spending hoursl ooking at it i am not sure why there is a reaction force in the upper pulley and not in system 1. I am confused about how the sytems are different and how that changes my answer. 3. The attempt at a solution Well i already had the answer with me so i just kept doing and trying to get the same answer but although i managed to get case 1 and 2 i dont know fi i should treat the pulleys as object or whatever else is necessary for the second system.