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Q6.3-12CQ

Expert-verified
Found in: Page 219

College Physics (Urone)

Book edition 1st Edition
Author(s) Paul Peter Urone
Pages 1272 pages
ISBN 9781938168000

Suppose a mass is moving in a circular path on a frictionless table as shown in figure. In the Earth’s frame of reference, there is no centrifugal force pulling the mass away from the centre of rotation, yet there is a very real force stretching the string attaching the mass to the nail. Using concepts related to centripetal force and Newton’s third law, explain what force stretches the string, identifying its physical origin.

There is a real force acting on the string due to the mass of the mail.

See the step by step solution

Step 1: Definition of Centrifugal force

When a mass is rotated, the apparent outward force on it is called centrifugal force.

Step 2: Identification of origin based on centripetal force and Newton’s third law

The mass is moving in such a circular path where the force of friction plays no part, but a net centripetal force acts towards the center.

Also, as the nail is attached to an inextensible string, a net tension force acts on the string which pulls it outwards, and as known according to Newton’s third law of motion, every action must have an equal and opposite reaction. Therefore, this tension force and the centripetal force both are equal and act in opposite directions to each other. Thus, there is a real force acting on the string due to the mass of the mail.