m = 70 kg A B mB = 45 kg The two boxes are released from rest. The kinetic friction coefficent between box A and the 0 = 30 inclined surface is k = 0.25. (Assume the pulley and rope have negligible mass.) i) If box B falls 400 mm, find the work done by gravity on box B. (Ug)B = ii) If box B falls 400 mm, find the work done by gravity on box A. (Ug)A = iii) If box B falls 400 mm, find the work done by friction on box A. (Uk)A = iv) If box B falls 400 mm, find the final speed of box A. |VAI =