Question

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

• A. $gL$
• B. $2gL$
• C. $\sqrt{gL}$
• D. $\sqrt{2gL}$

Answer 1

The correct option is D $\sqrt{2gL}$

Applying work energy theorem between the lowest and highest points of the trajectory:
$mgL=\frac{1}{2}m{v}_0^2$

or, $v_0=\sqrt{2gL}$