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## AP®︎/College Physics 1

### Course: AP®︎/College Physics 1>Unit 4

Lesson 3: Centripetal forces

# Centripetal forces review

Review the key concepts, equations, and skills for centripetal forces, including that centripetal force is the net force in the radial direction.

## Key terms

Term (symbol)Meaning
Centripetal force (${F}_{c}$)Net force acting in the direction towards the center of a circular path, causing centripetal acceleration. Direction is perpendicular to the object’s linear velocity. Also sometimes called radial force.

## Equations

EquationSymbol breakdownMeaning in words
$\mathrm{\Sigma }{F}_{R}=m{a}_{c}$${a}_{c}$ is centripetal acceleration, $m$ is mass, and $\mathrm{\Sigma }{F}_{R}$ is net force in radial direction (or centripetal force)Net radial force is directly proportional to the product of the object's mass and centripetal acceleration.

## Common mistakes and misconceptions

• Centripetal force is not a type of force. Centripetal force is a net force is the sum of the force vectors pointing in the radial direction. It could be the component of a force, the sum of multiple forces, or the difference of two radial vectors.
• People mistakenly think objects moving in a circular path are acted upon by an outwards pointing force. When you turn in a circle, it may feel like something is pulling you outwards from the turn, but that’s your inertia trying to resist a change in motion.