Question

A sphere is suspended by a thread of length $l$. What minimum horizontal velocity is to be imparted to the sphere for it to reach the height of suspension?

• A. $\sqrt{gl}$
• B. $gl$
• C. $\sqrt{2gl}$
• D. $\sqrt{l/g}$

Answer 1

Answer: (C)

$\sqrt{2gl}$

let velocity be V

$\begin{array}{c}\therefore \text{Conserving energy at point}A\text{\&}B\\ \frac{1}{2}m{v}^2=mgl\\ \text{on}V=\sqrt{2g1}\end{array}$

Ans C