Question

A block of mass m is released from rest on smooth track at height 5h. The speed of the block at point P shown on the circular track of radius r is

• A. $\sqrt{g(5h-r)}$
• B. $\sqrt{2g(5h-r)}$
• C. $\sqrt{g(5h-2r)}$
• D. $\sqrt{2g(5h-2r)}$

Answer 1

The correct option is D $\sqrt{2g(5h-2r)}$

Given,

Height, $h=5h$ and mass $=m$

Then,

$mg{h}_1=\frac{1}{2}m{v}^2+mg{h}_2$

$5gh=\frac{1}{2}{v}^2+g2r$

$\frac{1}{2}{v}^2=g(5h-2r)$

$v^2=2g(5h-2r)$

$v=\sqrt{2g(5h-2r)}$