Physics Chapter: Circular Motion

Uniform Circular Motion

• Circular motion occurs when an object travels along a circular path.
• Uniform circular motion is when an object moves in a circle at a constant speed.
• The direction of the object is constantly changing.
• Objects in uniform circular motion experience acceleration directed towards the center of the circle. This is called centripetal acceleration.
• The speed of the object does not change.

Centripetal Force

• Centripetal acceleration is the acceleration that occurs when an object moves in a circle at a constant speed.
• The acceleration is always directed towards the center of the circle.
• Centripetal force is the net force that causes the centripetal acceleration.
• This force is also directed towards the center of the circle.

Average Speed

• The average speed of an object in circular motion is calculated by dividing the circumference of the circle by the time it takes for one revolution.
• Average speed = (2 * π * radius) / time (T)

Equations

• Centripetal Force = (mass * velocity²) / radius
• Centripetal Acceleration = (velocity²) / radius

Examples

• A 10-meter wire is swung in a circle. It takes 0.8 seconds to complete one revolution. The speed of the bulb is needed at different points of the wire.
• A runner is moving at 8.8 m/s and rounds a bend with a 25-meter radius. Determine the runner's centripetal acceleration.

Centrifugal Force

• Centrifugal force is a fictitious or apparent force.
• It acts outward away from the centre of the rotation in a rotating frame of reference.
• It is the apparent force that pushes an object away from the centre of rotation. This effect is apparent to the object in rotation but not to a stationary observer.