Question

Density of rubber is d. A thick rubber cord of length L and cross-section area A undergoes elongation under its own weight on suspending it. This elongation is proportional to

• A. dL
• B. Ad/L
• C. $A d / L ^ { 2 }$
• D. $d L ^ { 2 }$

Answer 1

Answer: (D)

$d L ^ { 2 }$

Answer 2

Increment in length$l = \frac { L ^ { 2 } d g } { 2 Y }$∴ $l \propto L ^ { 2 } d$