A piece of stone tied to a string is made to revolve in a circular orb

A piece of stone tied to a string is made to revolve in a circular orbit of radius r with other end of the string as the centre. If the string breaks, the stone will :

move away from the centre.

move towards the centre.

move along a tangent.

stop.

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC CAPF – 2016

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When an object is revolving in a circular orbit, its velocity at any point is directed tangentially to the circle at that point. The string provides the centripetal force required to keep the object moving in a circular path, constantly changing its direction. If the string breaks, this centripetal force is removed. According to Newton’s first law of motion (the law of inertia), an object in motion will continue in a straight line with constant speed unless acted upon by an external force. Therefore, the stone will move in a straight line along the direction of its instantaneous velocity at the moment the string breaks, which is tangential to the circular orbit.

Understanding inertia and tangential velocity in circular motion is key to predicting the motion of an object when the centripetal force is removed.

This phenomenon demonstrates Newton’s first law and the nature of velocity in circular motion. The stone does not move away from the center (that would imply a radially outward force, which doesn’t exist upon breaking), nor does it move towards the center (as the inward centripetal force is gone), nor does it stop (unless there is friction or air resistance acting).

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