A bob of mass m suspended by a light string of length L is whirled into a vertical circle as shown in figure . What will be the trajectory of the particle if the string is cut at
(a) Point B ? (b) Point C? (c) Point X?

Explanation

When the string is cut, centripetal force is no longer provided. The bob flies along the tangen to the arc at that point.
(a) When string is cut at B, the bob moves vertically downwards.
(b) When string is cut at C, initial vel. of bob is along the horizontal to the right as shown . Therefore, the bob follows a parabolic path with vertex at C.
(c) When string is cut at X, initial velocity is along tangent to the circle at X. The bob will follow a parabolic path with vertex higher than C.