Tiny to Vast
Momentum conservationReact · 1D mechanics

Two-Block Momentum Collision

Set two blocks moving on a frictionless plane, watch their collision, and compare the system momentum before and after impact.

Frictionless 1D plane

Time 0.00 s

Before impact
0123456789101112
m₁
m₂

Model assumption

No friction or external horizontal force. The coefficient of restitution controls how much kinetic energy remains.

Momentum before

+7.60 kg·m/s

Momentum after

+7.60 kg·m/s

Difference

+0.00 kg·m/s

Experiment controls
Adjust the bodies, then run the collision again.

Block 1 · cyan

2.0 kg
0.55
3.2 m/s
-25

Block 2 · amber

3.0 kg
0.55
0.4 m/s
-22
1.0 e
01

Calculated outcome

Block 1 after
−0.16 m/s
Block 2 after
+2.64 m/s
Kinetic energy retained
100.0%

Momentum difference < 10⁻¹⁰ kg·m/s

Simulation paused.

One more perspective

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Every toy changes one assumption. Try another and see what moves.

Fig. 01

Impact physics

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Fig. 02

Effects model

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Compare blast, thermal, and radiation zones for different yields and burst types.

What the model calculates

One system, one conserved total

With no external horizontal force, the total momentum before impact equals the total momentum after impact. The coefficient of restitution changes the final velocities and kinetic energy, but it does not change the system's total momentum.

Momentum equation

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂. Positive velocity points to the right; negative velocity points to the left.

Elasticity equation

The restitution value e compares separation speed after impact with approach speed before impact. Set e = 1 for an elastic collision or e = 0 for a perfectly inelastic one.

This educational model treats both blocks as rigid bodies in one dimension and ignores friction, rotation, and deformation.