Circular motion

In physics, circular motion is rotation with constant speed around in a circle: a circular path or a circular orbit. It is one of the simplest cases of accelerated motion. Circular motion involves acceleration of the moving object by a centripetal force which pulls the moving object towards the center of the circular orbit. Without this acceleration, the object would move inertially in a straight line, according to Newton's first law of motion. Circular motion is accelerated even though the speed is constant, because the velocity of the moving object is constantly changing.

Related Topics:
Physics - Circular motion - Rotation - Circle - Orbit - Acceleration - Centripetal force - Newton's first law of motion

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Examples of circular motion are: an artificial satellite orbiting the Earth in geosynchronous orbit, a stone which is tied to a rope and is being swung in circles (cf. hammer throw), a racecar turning through a curve in a racetrack, an electron moving perpendicular to a uniform magnetic field, a gear turning inside a mechanism.

Related Topics:
Geosynchronous orbit - Hammer throw - Racetrack - Magnetic field - Gear

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A special kind of circular motion is when an object rotates around its own center of mass. This can be called spinning motion, or rotational motion.

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Circular motion is characterized by an orbital radius r, a speed v, the mass m of the object which moves in a circle, and the magnitude F of the centripetal force. These quantities all relate to each other through the equation

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: F = {m v^2 over r}

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which is always true for circular motion.

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