A uniform cable of mass 'M' and length 'L' is placed on a horizontal surface such that its `(1/n)^(th)` part is hanging below the edge of the surface. To lift the hanging part of the cable upto the surface, the work done should be:

Options

A. `(MgL)/(2n^2)`
B. `(MgL)/(n^2)`
C. `n MgL`
D. `(2 MgL)/(n^2)`

Answer

A

Explanation

Work-done will be equal to rise in potential energy of suspended section
`:. W = (mg)/L xx L/n xx L/(2n) = (MgL)/(2n^2)`.