newtons cradle

[steveb]

how come when you lift two balls up on one side and let them go two go up on the other side? why doesnt one just move off with twice the momentum?

cheers steve

[mibn2cweus]

I can see some interesting answer possibilities here once we get this ball rolling, so here's my guess:

The 2 causual balls act as a unit imparting an equal and opposite reaction on the other side.  Any balls in the center act as transporters of this unit force.  Now who has the real answer?

[mibn2cweus]

physics.org  has a discussion on this.  Use easy ask "how does newtons cradle work".

[Space]

my answer:
if one ball moved off with twice the momentum,
it would have twice the kinetic energy, witch isn't possible ( the cradle doesn't generate energy ).
One ball moving at velocity 2v has twice the kinetic energy as 2 balls moving at velocity v.
( because kinetic energy is in proportion with the velocity squared )