Question

A uniform chain of length L and mass M is lying on a smooth table and (1/4)th of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is 

(A) MgL 

(B) MgL/9 

(C) MgL/18 

(D) MgL/32

Answer 1

Correct option: (D) MgL/32

Explanation:

W = {(mgℓ) / (2n²)}

here m = mass = M, ℓ = length = L

n = fraction of length hanging from table since (1/4)th length is hanging

n = 4

W = [{MgL} / {2(4)²}] = {(MgL) / (32)}