Question

The string of a simple pendulum is horizontal. Now it is released. The tension in the string in the lowest position is :

• A. $2mg$
• B. $6mg$
• C. $3mg$
• D. $4mg$

Answer 1

Answer: (C)

$3mg$

$\begin{array}{c}\text{let, the mass of bob}=m\\ \text{length of pendulum}=1\\ \text{at the lowest point}\\ \begin{array}{c}\text{mgl}=\frac{1}{2}m{v}^2\\ \text{on}v=\sqrt{2gl}\end{array}\end{array}$

$\begin{array}{c}\text{on}\frac{v}{l}=w=\sqrt{\frac{2g}{d}}\\ \text{at the lowest point Tension}\\ T=m{\omega }^{2}l+mg\\ \text{of}T=m\frac{2g}{l}l+mg\\ \text{on}T=3mg\end{array}$

Ans. C