A simple pendulum of length l has a Bob of mass m. It is released from

1.	A simple pendulum of length l has a Bob of mass m. It is released from the horizontal position. The tension in the string at the lowest point is
Answer» Answer: Tension in the string at LOWEST point is 3mg Explanation: Length of the pendulum = l Mass of the BOB = m Let the velocity at the lowest position is v The bob is RELEASED from the horizontal position then its POTENTIAL energy will be converted into kinetic energy at the lowest position $mgl=\frac{1}{2}mv^2$ $\implies v^2=2gl$ the CENTRIFUGAL acceleration at the lowest point $=m\frac{v^2}{l}$ $=m\frac{2gl}{l}$ $=2mg$ The tension in the string at the lowest point = Weight of the bob + Tension due to centrifugal force $=mg+2mg$ $=3mg$