A simple pendulum oscillates simple harmonically. The tension in the string at lowest point is T. What is the total acceleration of the bob at its lowest position ?

Explanation

There are two components of acceleration, when the bob is moving under angular SHM. One is centrepital acceleration and other one is tangential acceleration.

At its mean position (lowest point), Tangential acceleration = 0
It will have only Centripetal acceleration
Net centripetal force = T - mg
Centripetal acceleration `= (T - mg)/(m)`
`= ((T - mg)/(m)) - T//m - g`