3D Recoil and Explosions Simulation

Recoil & Separation · Live

PhaseStoredTotal momentum0.0 kg·m/sKinetic energy0.0 JCentre of mass0.00 mm₁v₁ + m₂v₂ = constant

Momentum · Internal energy · Equal impulses · Centre of mass

Momentum-separation laboratory

Mission: release two spring-loaded carts from rest and verify that their momenta are equal in magnitude and opposite in direction.

Recoil or explosion example

Blue mass m₁2.0 kg

Orange mass m₂2.0 kg

Released internal energy120 J

Initial system velocity0.0 m/s

Separation direction0°

Simulation speed1×

Live measurements

Blue velocity0.00 m/s

Orange velocity0.00 m/s

Blue momentum x0.00 kg·m/s

Orange momentum x0.00 kg·m/s

Total momentum x0.00 kg·m/s

Total kinetic energy0.00 J

Equations with live values

p before = (m₁ + m₂) × V₀

p after = m₁v₁ + m₂v₂

From rest: m₁v₁ = −m₂v₂

Δp₁ = −Δp₂

Released energy = K after − K before

Momentum is conserved for the isolated system. Kinetic energy can increase because stored internal energy is converted into motion.

Momentum and energy graph

Total momentumKinetic energy

Camera and focus

Focus: noneTap an object or arrow

Zoom1.0×

Tap either part, an impulse arrow, the energy source, exhaust particles, or the centre-of-mass marker for a short explanation and close-up. Drag empty space to pan.

Teacher / Demo tools

Interactive visual lecture

A five-second prediction hook comes first. Each spoken idea is paired with recoil motion, impulse arrows, an energy transformation, an equation, or a focused microscopic view.

Language

Narrator

Narration speed1×

Ready. Embedded offline audio is available.

Step 0 of 100%

Choose a chapter

What to watch: equal impulses, opposite momenta, and moving centre of mass.

Select a chapter or start the complete lecture.

Chapters

Learn recoil step by step

Choose the system: include both objects or include vehicle plus exhaust.
Find momentum before: multiply each mass by its velocity and add directions.
Apply conservation: total momentum after equals total momentum before when external impulse is negligible.
Compare speeds: equal opposite momentum usually gives the lighter part the greater speed.
Use energy separately: stored elastic, pressure, chemical, or muscle energy determines how much kinetic energy appears.

Eight examples you can run

Spring carts: stored elastic energy creates opposite cart motion.
Astronaut and toolbox: a throw produces recoil in nearly frictionless space.
Balloon and air: pressure expels air and the balloon moves oppositely.
Spacecraft modules: separation occurs while the whole system is moving.
Two fragments: momentum is conserved in both horizontal and vertical directions.
Skater and medicine ball: unequal masses show why speeds are not equal.
Fire-extinguisher cart: a stream of gas produces continuous recoil.
Water rocket: downward exhaust momentum gives the rocket upward momentum.

What stays the same, and what can change?

Total momentum stays the same for the isolated system. Individual momentum, velocity, and kinetic energy can change. Kinetic energy can increase because stored internal energy becomes motion.

Suggested experiments

Start with equal masses, then make one mass four times larger.
Double released energy and compare the new speeds.
Give the spacecraft an initial velocity and track the centre of mass.
Use the angled fragments and verify both x and y momentum components.
Compare the balloon, extinguisher, and water rocket as three pressure-driven examples.

Common mistakes

Equal forces do not guarantee equal accelerations when masses differ.
Equal opposite momenta do not usually mean equal speeds.
Momentum conservation applies to the complete system, not one chosen object alone.
An explosion can increase kinetic energy without creating net momentum.

Check your understanding

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