Question

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

• 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 maximum compression in spring when the speed of the block is maximum And this happens only when the force of spring is equals to force exerted by the block on the string.

$Kx=mg\cos \theta$

$X=\frac{mg\cos \theta }{k}$