Question

When a stone is tied to a thread and the thread is rotated at a constant speed, when the thread is released why does the stone move along a straight line tangential to the circular path ? does it offer intertia ? if yes then why does it continue to move in a circular path ?

Answer 1

The stone is moving in circle because an external force called the centripetal force is acting on it due to the tension in the string but as soon as the tension is removed the stone carries on its journey in the direction of the velocity at that particular instant, which happen to be in tangential direction because in a circular motion the linear velocity is always tangential to the circle in which the body is moving.