Circular Motion Simulator — Centripetal Force & Tether Release Interactive

Interactive 3D laboratory spinning a puck on an ideal frictionless air table, with adjustable mass, radius and angular speed, a tether-release mechanism revealing tangent-line free flight, guided experiments, a model-verification bench and a knowledge-check quiz.

← Physics Labs
About this tool — how it works & FAQOpen ▾Close ▴

About the Circular Motion Simulator

This simulator places a puck on an ideal horizontal frictionless air table, connected to a central spindle by a massless inextensible tether. Adjust the puck's mass, the tether radius and the angular speed, then release the tether to compare the maintained circular path against the puck's free-flight motion along its instantaneous tangent.

What the simulator shows

• A real-time 3D air table with an angular scale, a central bearing and load cell, a sliding puck with mass inserts, a tether and release coupling, teal velocity and orange inward-force arrows, and a motion trail with a circular reference — with home view, focus-selected-part, auto-rotate, expand and toggleable labels. • Three live controls: puck mass (0.1–2 kg), tether radius (0.5–2 m) and angular speed (0–4 rad/s). • Seven live metrics: speed, acceleration magnitude, tether force, revolution period, x position, z position and kinetic energy. • A Curves & measurements tab charting speed and acceleration, the full model equations and snapshot measurements. • An Experiments tab with four guided scenarios (baseline circle, doubling angular speed, releasing from the start, zero angular speed), a model-verification bench of independent automated checks, and a timestamped event log with a copyable trial report. • A Learn & assess tab with guided lessons, a two-question knowledge-check quiz and a written scope/reference statement.

Acceleration without a change in speed

Uniform circular motion changes velocity's direction continuously even while speed and kinetic energy stay exactly constant — velocity is a vector, and turning it counts as acceleration. That inward acceleration is ac = ω²r = v²/r, and the tether supplies the inward force T = mω²r needed to produce it. "Centripetal" describes the inward role this force plays, not a separate force added on top of tension — in this lab, tension is the centripetal force, in full.

What happens the instant the tether is released

The moment the tether releases, the horizontal constraint force drops to zero — there is no inward force left, so the puck stops turning and instead continues in a straight line along whatever velocity it had at that exact instant (its tangent to the circle). Doubling the angular speed from 2 to 4 rad/s doubles the puck's speed but quadruples the required tether force, since force scales with ω squared — confirmed directly in the doubling experiment.

Frequently asked questions

What happens to a puck immediately after its tether is released?

It stops moving in a circle and instead follows its tangent — traveling in a straight line at the constant velocity it had at the exact instant of release. Removing tension removes the inward force and therefore the inward acceleration, but velocity itself does not jump; it is continuous across the release.

If you double the angular speed at a fixed radius, how does the required tether force change?

It increases by a factor of four, not two. The tether force is F = mω²r, so doubling ω while holding mass and radius fixed multiplies the required force by 2² = 4 — you can confirm this directly in the doubling-angular-speed experiment.

Is centripetal force a separate force added on top of the tether tension?

No. "Centripetal" describes the inward role a force plays, not an additional force to sum alongside tension. In this simulator, the tether tension is the centripetal force — there is nothing else to add.

What does this circular-motion model leave out?

It is an idealized model on a horizontal frictionless plane with a massless inextensible tether and a preset initial velocity — spin-up is not simulated, release applies no impulse, and free flight after release is mathematically continued to a ±4 m display boundary with no modeled edge drop or impact.

Related tools & guides