Newton's Cradle · The Cavern

Newtonian drift — brass cradle

Lift k balls from one end and let go; k balls fly out the far side at the same speed. That is the unique outcome that conserves both momentum and kinetic energy at once. Dial the bounce below 1 and watch energy bleed away, one honest step per click — while momentum is still conserved exactly.

The cradle

Ball count N 5

Lift & release 1 from left

1ball

The collision

Restitution e 1.00 · perfectly elastic

Conservation

kinetic KE0.000 J

potential PE0.000 J

total E = KE+PE0.000 J

momentum p0.000 kg·m/s

Δp at last click—

energy E = KE+PE momentum p

Try it: drag any ball aside and let go, or click a ball to lift that many from its end. At e = 1 the energy line is flat and the click-clacks ring on forever. Pull e down and the energy line stair-steps down at every click — momentum p still balances exactly. Make one end ball heavy and the tidy "k out" rule breaks, yet both ledgers stay closed.