A heavy rope, 40 ft long, weighs 0.5 lb/ft and hangs over the edge of a building 90 ft high. (Let x be the distance in feet below the top of the building. Enter x_i* as x_i.)
(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.
lim (n -> inf) sum (i=1 to n) (5/10 x_i) dx
Express the work as an integral:
integral (0 to 40) (5/10 x) dx
Evaluate the integral: 400 ft-lb
(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.
lim (n -> inf) sum (i=1 to n) (0.5(x_i + 20)) dx
Express the work as an integral:
integral (0 to 20) ( ) dx
Evaluate the integral:
ft-lb