Circular motion is the movement of an object along the circumference of a circle. In this type of motion, the object maintains a constant distance from the center of the circle, which we call the radius. As you can see, the object traces a circular path while staying at the same distance from the center point.
Circular motion has several key parameters. The period T is the time required for one complete revolution. Frequency f is the number of revolutions per second, and equals one over T. Angular velocity omega measures how fast the angle changes with time, and equals two pi divided by the period.
In circular motion, we distinguish between tangential velocity and angular velocity. Tangential velocity v is the speed of the object along the circular path, always directed tangent to the circle. It equals omega times r. Angular velocity omega measures how fast the angle changes, and equals v divided by r. The units are radians per second.
For an object to maintain circular motion, it requires centripetal acceleration directed toward the center. This acceleration equals v squared over r, or omega squared times r. The centripetal force needed equals mass times centripetal acceleration. Both acceleration and force always point toward the center of the circle.
To summarize what we've learned about circular motion: Objects move in circles maintaining constant distance from the center. The motion is characterized by period and frequency. Velocity is always tangent to the path while centripetal force points inward. These principles apply to many real-world systems from satellites to rotating machinery.