One-dimensional forces meet two-dimensional motion

Circular Motion Studio

Rotate the position on an ideal circular path and compare the tangential velocity arrow with the inward acceleration vector.

Safety and scientific scope

For uniform circular motion, inward acceleration magnitude a_c=v²/r and net radial force requirement F_c=mv²/r. The arrows point tangent and inward, respectively. 'Centripetal force' is a description of the net inward force supplied by real agents; do not add it as an extra arrow on a free-body diagram already accounting for the actual inward forces.

1. Choose parameters and predict

2. Position, velocity and inward acceleration

Teal: tangential velocityOrange: radial accelerationBlue: circular path

Vector lengths are indicative; velocity and acceleration have different units. Changing the phase shows the directions rotating at fixed speed, and does not change their magnitude.

Calculated model components (not measured)
QuantityX componentY componentUnit

3. Plot the square-speed relation

At fixed mass and radius, inward-force requirement is proportional to speed squared (including when the force-source capacity is inadequate).

Calculated inward force as speed changes (mass and radius held fixed)
Speed (m/s)Required inward force (N)Max lateral static-friction model (N)

4. Model evidence notebook

Locally saved synthetic circular-motion trials
#Mass (kg)Speed (m/s)Radius (m)μ_sRequired force (N)Flat-road ideal constraint

Download mathematical circle-data CSV

5. Seven-Round Circular-Force Game

Seven different calculation problems drawn at random from eleven. Calculate F=m v²/r in newtons. This is an educational arithmetic model, not a real trajectory planner.

Start a new challenge.

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