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Ball Rolling Down a Ramp: Roll vs. Slip Physics (2D)

2D rolling-ball lab: a Coulomb-friction slip test run every physics step decides whether the ball is sliding or truly rolling, with live speed, spin, distance and slip-margin readouts across three ball materials.

Everyday Physics2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

This 2D companion replaces the 3D version's rigid-body physics engine (Cannon-es) with a transparent, hand-derived Coulomb-friction model: every step it tests the contact-point slip velocity against the material's static-friction limit to decide whether the ball is genuinely sliding or rolling without slipping, exposing the (2/7)·tanθ vs. μ inequality that governs the transition directly as a live readout, alongside speed, spin, distance and elapsed time, across three ball materials that each carry their own mass, friction and rolling-resistance values.

⚙ Under the hood

2D rolling-ball lab: a Coulomb-friction slip test (v_s = v − ωR) run every physics step decides between kinetic sliding friction and the analytic pure-rolling friction (2/7)mg·sinθ, integrated with a fixed 1/300s sub-step; a separate rolling-resistance term keeps decelerating the ball even once it rolls cleanly, so it comes to a real stop instead of coasting forever.

rolling motioncoulomb frictionstatic vs kinetic frictionrolling resistancerigid-body dynamicsimpulse-momentum theorem

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install