Circular motion notes

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Definitions

Circular motion: An object is undergoing circular motion if it travels in a circular path due to a centripetal force changing its direction at a constant rate.

Centripetal force: a force which acts at right angles to the direction of motion of the object, such as the tension in a string or a gravitational force.

Circular motion

During circular motion, the object is accelerating because acceleration is the rate of change of velocity, which is a vector quantity. Although the velocity doesn't increase or decrease in magnitude, it constantly changes direction and is therefore accelerating.

The velocity of the object will not change due to the centripetal force because the centripetal force always acts at right angles to the direction of travel, and so it does no work on the object.

Angular displacement

The angle that the object has moved through, denoted

by change in theta in radians.

Angular velocity

the rate of change of angular displacement, denoted by

ω in rads^-1

Time period

Time taken for the object to complete one whole rotation.

ω=2pi/T

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