The Total solution for NCERT class 6-12
A bob of mass 0.1 kg hung from the ceilingof a room by a string 2 m long is set into oscillation. The speed of the bob atits mean position is 1 m s–1. What is the trajectory of the bob ifthe string is cut when the bob is (a) at one of its extreme positions, (b) atits mean position.
Answer: (a) Vertically downward
(b) Parabolic path
(a) At the extreme position, the velocity of thebob becomes zero. If the string is cut at this moment, then the bob will fallvertically on the ground.
(b)At the mean position, thevelocity of the bob is 1 m/s. The direction of this velocity is tangential tothe arc formed by the oscillating bob. If the bob is cut at the mean position,then it will trace a projectile path having the horizontal component ofvelocity only. Hence, it will follow a parabolic path.