9514 1404 393
Answer:
1800 ft·lb
Step-by-step explanation:
The weight of the chain is ...
(4 lb/ft)(30 ft) = 120 lb
The center of mass of the hanging chain is its midpoint, 30/2 = 15 ft below the winch. The work done winding the chain is the work done lifting the center of mass 15 ft to the winch:
(120 lb)(15 ft) = 1800 ft·lb
