Explore the Circular Motion & Centripetal Force
Swing a ball on a string and drag it to change the radius and speed. Free, no signup, runs in your browser.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The Circular Motion & Centripetal Force with sample data entered and the result showing.
What is the Circular Motion & Centripetal Force?
Swing a ball on a string and drag it to change the radius and speed. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
Circular motion appears in cars on bends, satellites, washing machines, roller coasters and ultra-centrifuges.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Centripetal acceleration is a = v² / r = ω² r and points to the centre.
Centripetal force F = m v² / r. It is not a new force: it is whatever pulls the object inward.
If the string is cut the ball flies off in a straight line along the tangent.
Drag the ball outward to double the radius and watch the force change.
Double the angular speed. By what factor does the force grow?
Press Cut string and see the tangent path.
Used for
Pick one to see how it fits.
Physics learners
Physics students in middle school, high school and first-year university, teachers who want a quick demonstration for the projector, and anyone revising for exams.
Try it freeTeachers
For teachers: project the Circular Motion & Centripetal Force on the board, let students predict the result, then run it together and test this: Double the angular speed. By what factor does the force grow?. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
Why does the velocity change if the speed is constant?
Velocity is a vector. Its direction keeps changing as the ball goes around, so there is an acceleration pointing to the centre.
What happens when the string breaks?
There is no inward force any more, so the ball moves in a straight line along the direction it was going at that instant.
Is the Circular Motion & Centripetal Force free to use?
Yes. The Circular Motion & Centripetal Force is free, needs no signup or download and runs in your web browser. It is part of the Physics group of AZRS simulations.
Does the Circular Motion & Centripetal Force work on a phone or tablet?
Yes. The Circular Motion & Centripetal Force takes touch input as well as mouse input, so you can use its 3 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
How do I use the Circular Motion & Centripetal Force?
1. In the Circular Motion & Centripetal Force, use the controls to change Angular speed ω, Ball mass, Radius. The simulation reacts instantly. 2. In the Circular Motion & Centripetal Force, pick an option such as Velocity, Acceleration / force, Trail to switch modes or load an example. 3. In the Circular Motion & Centripetal Force, press "Cut string", "Reset" to start, reset or change what is happening. 4. Start with this experiment: Drag the ball outward to double the radius and watch the force change. Drag any glowing handle, object or slider with your mouse or finger and the Circular Motion & Centripetal Force responds in real time. 5. Change one setting at a time and watch which readout moves, then compare it with this idea: Centripetal acceleration is a = v² / r = ω² r and points to the centre.
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Try the Circular Motion & Centripetal Force now
Swing a ball on a string and drag it to change the radius and speed. Free to use.
Try it free