A simple pendulum is a point mass suspended by a light thread from a fixed point. The particle is displaced towards one side and then released. It makes small oscillations. Is the motion of such a simple pendulum a pure rotation? If yes where is the axis of rotation?
Answers
Answer ⇒ Yes, the motion of such a simple pendulum is a pure rotation.
Explanation ⇒ As we know that in a pure rotation all the particles of a body always moves in concentric circles, thus such motion of a simple pendulum is always a pure rotation but only the direction of motion reverses periodically.
The axis of rotation in this case is the line perpendicular to the plane of rotation and passing through the fixed point where the thread of the pendulum is tied. Since the oscillations are small, for all practical purposes the movement of the ball can be assumed on a straight line and also the motion can be taken as periodic and Simple Harmonic motion can be assumed.
Hence, we can finally say that the motion of such a simple pendulum a pure rotation.
Hope it helps.