Question

A uniform chain of length 2 m is kept on a table such that a length of 50 cm hangs freely from the edge of the table. The total mass of the chain is 5 kg. What is the work done in pulling the entire chain on the table. (g = 10 m\s²) 

(A) 7.2 J 

(B) 3 J 

(C) 4.6 J 

(D) 120 J

Answer 1

Correct option: (B) 3 J

Explanation:

Workdone = W = {(mgl) / (2n²)}

n = fraction of length of chain hanging from table total length = 2 m

hanging length = 0.5 m

hence n = 4

W = [{(5) (10) (2)} / {(2) (4)²}] = {(50) / (16)} = 3.125 ≈ 3J