Question

The string of pendulum of length I is displaced through ${90}^{\circ }$ from the vertical and released. Then the minimum strength of the string in order to withstand the tension, as the pendulum passes through the mean position is

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

T = mg + $\frac{m{v}^2}{l}$ = mg + 2mg = 3mg
where v = $\sqrt{2gl}$ from $\frac{1}{2}$$m{v}^2$ = mgl