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For K-12 Students · Collision Lab

Collision Lab for a playground swing

Built for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework. Simulate a playground swing live below — adjust the inputs and watch it respond, right in your browser.

Collision Lab (1D)Live

momentum is always conserved

Controls

Presets

Mass 1 (kg)

Mass 2 (kg)

Velocity 1 (m/s)

Velocity 2 (m/s)

Restitution e

Momentum is conserved in every collision. Kinetic energy is conserved only when e=1 (perfectly elastic); at e=0 the carts stick together and the lost energy becomes heat and sound. Drag either cart on the canvas to set where it starts.

▶ Run in Python

Data Inspector

Final v₁0.33 m/s

Final v₂4.33 m/s

KE before9.5 J

KE after9.5 J

Energy lost0%

Governing equation

v_{1}^{'} = \frac{m _{1} u _{1} + m _{2} u _{2} - m _{2} e ( u _{1} - u _{2} )}{m _{1} + m _{2}} = 0.33, v_{2}^{'} = \frac{m _{1} u _{1} + m _{2} u _{2} + m _{1} e ( u _{1} - u _{2} )}{m _{1} + m _{2}} = 4.33

Reading this result: This collision is elastic (e=1), so kinetic energy is fully conserved; momentum-sharing only redistributes the speeds between the two masses.

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Frequently asked questions

Is this good for k-12 students?: Yes — this version of "Collision Lab for a playground swing" is framed for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.