A 10ft chain weighs 30 lb and hangs from a ceiling Find the

A 10-ft chain weighs 30 lb and hangs from a ceiling. Find the work done in lifting the lower end of the chain to the ceiling so that it is level with the upper end.

Solution

work = integration ( (M/L)gxdx ) [x from 0 to L)

= (M/L) g L^2/2

= MgL/2

= 30 * 10/2 = 150 lb-ft