Question

A 12-ft chain weighs 24 lb and hangs from a 10-ft high ceiling. Find the work needed to lift the lower end of the chain to the ceiling so that it is level with the upper end

Answer 1

Explanation:

We shall calculate work needed by knowing the distance by which centre of mass has been raised in the process .

center of mass is raised by

( 10 / 2 - 6 / 2 ) = 2 ft

h = 2 ft

g = 32 ft/s²

m = 24 lb

Work done = mgh

= 24 x 32 x 2

= 1536 units.