Centripetal force

Definition

Centripetal force is the force that keeps an object moving in a circular path, directed towards the center of the circle. It is necessary for maintaining uniform circular motion.

5 Must Know Facts For Your Next Test

1. Centripetal force is always directed perpendicular to the velocity of the object and towards the center of the circular path.
2. The magnitude of centripetal force can be calculated using $F_c = \frac{mv^2}{r}$, where $m$ is mass, $v$ is velocity, and $r$ is radius.
3. Centripetal force does not do work on the object because it acts perpendicular to its displacement.
4. In the context of gravity, centripetal force can be provided by gravitational attraction, such as a planet orbiting a star.
5. If centripetal force ceases to act, an object will move in a straight line tangent to its circular path due to inertia.

Review Questions

• What direction does centripetal force act in relative to an object's velocity?
• How is centripetal force related to mass, velocity, and radius?
• What happens to an object's motion if centripetal force stops acting on it?

Related terms

Uniform Circular Motion: Motion in a circular path at constant speed.

Centrifugal Force: A fictitious force perceived in a rotating reference frame that appears to push an object outward from the center.

Gravitational Force: The attractive force between two masses due to gravity; can act as a centripetal force in orbital motion.