How is a particle moving in circular motion accelerating but not varying speed?

When a particle moves in circular motion, the resultant centripetal force acts radially towards the centre of the circle. Since there is a force there must be an acceleration on the particle due to Newtons 2nd law. However if you were to analyse the particles movement you would observe that the time period stays constant, showing that the speed is constant. Therefore the question is, how is an acclerating particle not varying speed? The answer behind this comes from the fact that acceleration and velocity are vector quantities, meaning they have a magnitude and direction. The velocity of the particle acts in the direction of the tangent to the circle and is therefore perpendicular to the force. Due to the force and velocity being perpendicular from one another there is no work done on the particle, because the particle doesn't change energy then it cannot change speed. The change in velocity comes from the particle's velocity changing direction around the circle rather than its magnitude. 

MS
Answered by Max S. Physics tutor

3597 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Why does a feather fall at the same rate as a hammer on the Moon?


A Uranium-(238,92) nucleus decays into a Thorium-234 nucleus by the emission of an alpha-particle. Given Thorium has a chemical symbol Th build a nuclear equation.


Two balls with the same kinetic energy have mass of ball a = m and ball b = 2m. What is the ratio of their momentums: a/b?


How to determine the total time of flight for a projectile launched at an angle theta to the horizontal with an initial speed u?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences