Question

A bob is suspended by a string of length l. The minimum horizontal velocity imparted to the ball for reaching it to the height of suspension is

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

Answer 1

Answer: (B)

$\sqrt{2gl}$

applying the energy conservation principle. The kinetic energy provided will change into gravitational potential energy i.e.
$\frac{1}{2}m{v}^2=mgl\Rightarrow v=\sqrt{2gl}$