Question

A ball of mass mm is hung on a thread. The thread is held taut and horizontal, and the ball is released as shown. What is the tension in string when it becomes vertical?At what angle between the thread and vertical will the tension in thread be equal to weight in magnitude?

Answer 1

When the string becomes vertical, the tension in the spring is exactly balanced by the gravitational force on the ball.

$\therefore T=mg=W$

This happen when the angle between the thread and vertical is $0$.