Question

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

Options

• 12 J

• 3.6 J

• 7.2 J

• 1200 J

Answer 1

3.6 J

Explanation:

Mass of over hanging part of the chain

m' = `4/2xx(0.6)`kg = 1.2 kg 

Weight of hanging part of the chain = 1.2 × 10 = 12 N

C.M. of hanging part = 0.3 m below the table

Work done in putting the entire chain on the table = 12 × 0.30

= 3.6 J.