Question

Let θ denote the angular displacement of a simple pendulum oscillating in a vertical plane. If the mass of the bob is m, the tension is the string is mg cos θ
(a) always
(b) never
(c) at the extreme positions
(d) at the mean position.

Answer 1

(c) at the extreme positions

Tension is the string, $T=\frac{m{v}^2}{r}-mg\cos \theta$
When v = 0, $\left|T\right|=mg\cos \theta$
That is, at the extreme positions, the tension is the string is mgcosθ.