Centripetal force and circular motion calculator
Enter the mass, speed and path radius, for a car on a curve or a stone on a string.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter mass, speed unit, speed and path radius.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
a = v² ÷ r, F = m × v² ÷ r, ω = v ÷ r, period T = 2πr ÷ v.
Example
Inputs: Mass = 1,000 kg, Speed unit = Meters per second (m/s), Speed = 20, Path radius = 50 m. Result: Centripetal force: 8,000 N; Centripetal acceleration: 8 m/s²; Angular velocity: 0.4 rad/s.
Limits and caveats
- Assumes uniform circular motion at constant speed.
- Gives the required centripetal force only, not where it comes from, such as friction or string tension.
Questions about this tool
What supplies the centripetal force for a car on a curve?
Friction between the tires and the road. If the car needs more than the available friction, it slides outward.
Is centrifugal force real?
It is an apparent force felt inside the rotating object. Seen from outside, only the centripetal force toward the center acts.
What happens if the speed doubles?
The centripetal force goes up four times because speed is squared, which is why slowing before a bend matters.