Circular motion

What is circular motion?

Motion in a circular path

What is linear speed/velocity?

The rate of change of distance of the object in a straight path. It acts at a tangent to the circular path of the object.

What is angular speed / velocity?

The rate of change of angle of an object.

(How quickly the object is changing its angle/direction)

What is centripetal force?

The resultant force acting an object that keeps it moving along a circular path. It acts perpendicular to the direction of (linear)velocity.

What are the equations for linear velocity?

(2πr)/T or 2πrf

Why does the speed of an object stay constant during circular motion? And why does the velocity change?

• The centripetal force does not act in the same direction of the speed, therefore there is no acceleration

• However, the direction of the object is constantly changing. Speed is a scalar but velocity is a vector, therefore if the direction changes, the velocity changes.