The uniform slender bar ABC weighs 6 lb and is intially at rest with end A bearing against the stop in the horizontal guide. When a constant couple M=72 lb-in is applied to end C, the bar rotates causing end A to strike the side of the vertical guide with a velocity of 10ft/sec. Calculate the loss of energy E due to the friction in the guides and rollers. The mass of the rollers may be neglected.