Circular motion

Circular Motion — Physics Notes

1. Uniform Circular Motion

Uniform circular motion occurs when an object moves in a circle at constant speed.

Key property:

• Speed remains constant

• Velocity changes continuously because direction changes

Velocity is always tangent to the circular path.

Centrifugal Force (Misconception)

Centrifugal force appears to push objects outward, but it is not a real force acting on the object.

Reason:

• Objects naturally move in straight lines due to inertia

• The inward centripetal force keeps them moving in a circle

If centripetal force disappears (e.g., string breaks):

• The object moves tangent to the circle, not outward.

This follows Newton's First Law of Motion.

Sources of Centripetal Force

Different forces can act as centripetal force depending on the system.

Examples: