Centripetal Force
The net inward force that keeps an object on a circular path.
About this topic
Centripetal force is not a new force but the name for the net inward force that keeps an object on a circular path, F = mv²/r. It may be tension in a string, friction on tyres, gravity on a satellite, or a normal force.
If it vanishes, the object flies off in a straight line along the tangent, not outward. The force increases with mass and with the square of speed, and decreases with a larger radius. So doubling the speed needs four times the force. On a banked curve, part of the normal force supplies the inward push.
Example: a 1000 kg car takes a bend of radius 50 m at 20 m/s and needs F = 1000 x 400/50 = 8000 N from friction. If the road is icy and friction cannot supply it, the car skids straight on. The Moon is held in orbit by gravity, hammer throwers pull inward on the chain, and a bucket of water swung overhead stays full because of the inward force.
Misconception: centrifugal force is not a real force acting on the object; it is the apparent outward feeling in a rotating frame caused by inertia. Never draw centripetal force as an extra arrow on a free-body diagram; label the real force that supplies it.
Key ideas
- F = mv²/r
- Provided by tension, gravity or friction
- Not a new force type
Quick check
Use cases: where Centripetal Force helps
- Homework: review the key idea behind Centripetal Force before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Centripetal Force without notes.
- Visual learning: play with the interactive lab to see how Centripetal Force changes when you adjust its inputs.
- Teaching a friend: explain Centripetal Force in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Centripetal Force?
The net inward force that keeps an object on a circular path.
What will I learn in Centripetal Force?
F = mv²/r. Provided by tension, gravity or friction. Not a new force type.
Is Centripetal Force part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Centripetal Force lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Centripetal Force?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.