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?

• A. 7.2 J
• B. 3.6 J
• C. 120 J
• D. 1200 J

Answer 1

The correct option is B 3.6 J

Mass of the chain lying freely from the table=$M\frac{l}{L}$

$=4kg\times \frac{0.6}{2}$

$=1.2kg$

The distance of center of mass of chain from the table=$\frac{1}{2}\times 0.6m=0.3m$

Thus the work done in pulling the chain=$mgh=1.2\times 10\times 0.3J=3.6J$