# centripetal force

## noun

1. the force, acting upon a body moving along a curved path, that is directed toward the center of curvature of the path and constrains the body to the path.

centripetal force

## noun

1. a force that acts inwards on any body that rotates or moves along a curved path and is directed towards the centre of curvature of the path or the axis of rotation Compare centrifugal force
“Collins English Dictionary — Complete & Unabridged” 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

centripetal force

1. A force acting on a moving body at an angle to the direction of motion, tending to make the body follow a circular or curved path. The force of gravity acting on a satellite in orbit is an example of a centripetal force; the friction of the tires of a car making a turn similarly provides centripetal force on the car.

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## Word History and Origins

Origin of centripetal force1

First recorded in 1700–10
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## A Closer Look

In a popular carnival ride, people stand with their backs against the wall of a cylindrical chamber. The chamber spins rapidly, the floor drops out, but the riders remain pressed against the wall without falling. Although the riders may insist they stay aboard because of an outward force pushing them against the wall, the reality is the opposite: the riders are subject to an inward, or centripetal, force. As the ride spins, it forces the riders to travel in a circle. According to Isaac Newton's law of inertia, objects in motion tend to travel in a straight line at constant speed unless acted on by an external force. To make an object travel along a curved path, some force—the centripetal force—must push the object toward the center of curvature of that path. In the case of the circular path, the direction of the force is toward the center of rotation. The wall of the ride's cylindrical chamber accomplishes this by pushing the riders toward the center (with the friction between the riders and the wall holding the riders up). The force of the Earth's gravity acts as a centripetal force on orbiting objects, such as the Earth's Moon, which is constantly being accelerated toward the center of the Earth, as in free fall. The Moon has enough inertia not to plummet into the Earth but not so much that it can escape the Earth's pull, and thus it will orbit almost indefinitely.
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## Compare Meanings

How does centripetal force compare to similar and commonly confused words? Explore the most common comparisons:

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## Example Sentences

So inevitably the centripetal force of the establishment GOP will move toward Jeb Bush.

The centripetal force, exerted through the cord, O A, pulls it aside from this direction of motion.

It is true, the resistance of the body furnishes the measure of the centripetal force.

Sometimes the centripetal force is weak, and opportunity is afforded to observe this action, and see its character exhibited.

A common example of weak centripetal force is the adhesion of water to the face of a revolving grindstone.

That is, it has no motion, either from or toward the center, except that which is produced by the action of the centripetal force.