A heavy rope, 40 ft long, weighs 0.3 lb/ft and hangs over the edge of a building 110 ft high. (Let x be the distance in feet below the top of the building.) (a) How much work W is done in pulling the rope to the top of the building? Show how to approximate the required work by a Riemann sum. Express the work as an integral. Evaluate the integral. (b) How much work W is done in pulling half the rope to the top of the building? Show how to approximate the required work by a Riemann sum. Express the work as an integral. Evaluate the integral.