Question

A heavy uniform chain lies on a horizontal table top. If the coefficient of friction between the chain and the table surface is 0.25, then the maximum fraction of the length of the chain that can hang over one edge of the table is

• A. 20%
• B. 25%
• C. 35%
• D. 15%

Answer 1

Answer: (A)

20%

Answer 2

From the expression $l ^ { \prime } = \left( \frac { \mu } { \mu + 1 } \right) l$ $= \left( \frac { 0.25 } { 0.25 + 1 } \right) l$

[As μ = 0.25]

⇒ $l ^ { \prime } = \frac { 0.25 } { 1.25 } l$ $= \frac { l } { 5 }$ = 20% of the length of the chain.