A chain, with length h = 300 feet and weighing 7 pounds per foot, hangs over the side of a building. We are going to determine the work required to lift the chain to the top of the building. X= 0 Xi di IAX X= h This problem depends on the vertical coordinate system to the left. The force, Fi, on the i" strip of the chain = weight of the 2"" strip of the chain. Fi = pounds The distance, di, we are moving the it strip is di = feet (Must relate back to I; ). The work, Wi, required to lift the i" strip of the chain is Wi = Fi . di. Wi = ft-lbs Adding up the work on all the subintervals and allowing n - 00, where n represents the number of subintervals, gives the integral for total work, 11, required to lift the chain to the top of the building. W dx Finally, W = foot-pounds