Three blocks - A, B, and C - are connected by two ropes with tensions T1 and T2. Blocks A and B weigh 20 N each, and the coefficient of kinetic friction between each block and the surface is 0.40. Block C descends with constant velocity. (All pulleys are frictionless.) Draw free body diagrams for all blocks. Find the tensions T1 and T2 in the ropes. Find the mass of block C.