Question

A uniform chain of mass m and length l overhangs a table with its two third part on the table . Find the work to be done by a person to put the hanging part back on the table. Plzz explain it clearly

Answer 1

To put the chain back on table we need to work against its potential energy.
so, the potential energy of the overhanging part is the answer for your question.
In this question since one third part is hanging mass of hanging part is m/3
and this weight will be at centre of mass of hanging part.
l/3 is hanging part length.so,l/6 is its centre  of mass
then potential energy=mgh
                                   =m/3*g*l/6
                                   =mgl/18
so, it is the work required to put it on table.
if u dont understand ping me vl explain in more detail

Answer 2

see attachment...I hope it will helps...