Question

A block of mass ${}^{\prime }{m}^{\prime }$ is released from rest at point $A$. The compression in spring, when the speed of block is maximum:

• A. $\frac{mg\sin \theta }{k}$
• B. $\frac{2mg\sin \theta }{k}$
• C. $\frac{mg\cos \theta }{k}$
• D. $\frac{mg}{k}$

Answer 1

The correct option is C $\frac{mg\cos \theta }{k}$

The correct interpretation of this question is that the maximum compression in spring when the speed of the block is maximum And this happens only when the force of spring is equal to force exerted by the block on the string$,$

$Kx=mgcos\theta$

$X=\frac{mgcos\theta }{k}$

Hence,

option $\left(C\right)$ is correct answer.