A uniform chain of length 2m is kept on the table such that length of 60cm hangs freely from the edge of table. Total mass of chain is 4kg.What is work done in pulling the entire chain on table?

M = total  mass of the chain.

L =  total length of the chain.
M = 4 kg ,  L = 2 m

Take  length and mass of part of chain hanging down as  l and m respectively
so,

l = 0.6 m

So now  mass per unit length is

M/L = m/l

m = l / L * 4

m = (0.6 / 2) * 4

m = 1.2 kg 

Tension = mg

                = 1.2 *9.8

               = 11.76 N

Force required = Tension 

Displacement = 0.6 m

(part of chain hanging comes up)

W= Force x Displacement

w = 11.76 * 0.6

w = 7.056 J