Cart 1 moves toward stationary cart 2. Newton's second law
(F = ma) governs each cart's acceleration during contact; Newton's
third law means the force cart 1 exerts on cart 2 is equal and
opposite to the force cart 2 exerts back — the two arrows you see
during impact are always mirror images.
m1·v1 + m2·v2 = m1·v1' + m2·v2' (momentum conserved, always)
e = |v2' − v1'| / |v1 − v2| (restitution: 1 = elastic, 0 = fully inelastic)
F12 = −F21 (Newton's third law)
- Mass 1 / Mass 2 — inertia of each cart; heavier carts resist acceleration more (Newton's first law).
- Initial velocity — cart 1's launch speed before impact.
- Restitution — how bouncy the collision is; 1.0 conserves kinetic energy exactly, 0 means the carts stick together.