Two blocks with different mass are attached to either end of a light rope that passes over a light, frictionless pulley that is suspended from the ceiling. The masses are released from rest, and the more massive one starts to descend. After this block has descended a distance 1.40 , its speed is 1.50 . A. If the total mass of the two blocks is 18.0 , what is the mass of the more massive block? B. What is the mass of the lighter block? I know we probably have to use K_1 + U_1 + W_other = K_2 + U_2 but I'm not sure how so .. Please help me!