# 5.2 Circular Motion Flashcards

Define angular velocity

The rate of change of angle of an object moving in a circular path

Define centripetal force

The resultant force towards the centre of a circle

Define centripetal acceleration

Acceleration towards the centre of a circle that causes the resultant centripetal force

How are centripetal force and velocity related? (2)

Centripetal force always acts perpendicular to velocity

There is no component of force in the direction of motion so the speed remains constant

Why are objects in circular motion accelerating if they have constant speed?

The direction is constantly changing so their velocity is changing, meaning they have acceleration

How is linear velocity related to radius?

For any object with constant angular velocity, linear velocity is directly proportional to the radius

How can circular motion be investigated using a bung? (2)

Use a bung attached to a weight using a piece of string

Swing the bung in a horizontal circle so that the suspended weight stays stationary; mg = centripetal force

Motion in a vertical circle (3)

Centripetal force is constant at all points

At top of circle, centripetal force = tension + weight

At bottom of circle, centripetal force = tension - weight