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 in the string is mg cosθ  
(a) always (b) never (c) at the extreme positions(d) at the mean position.

Answer 1

(c) at the extreme positions 

Explanation:

At any position tension in the string is = mg.cosθ+mv²/r (Where r is length of pendulum and v is instantaneous velocity of bob) v is zero only at extreme positions. So tension is mg.cosθ only at extreme positions.