Why not the last ball in Newton's Cradle just fly higher when two bullets at the other end are left? I have the equal and opposite reaction orders, and I know there's more force when two balls are dropped from one end of a Newton's cradle, instead of one, but how come two balls at the other end are moved instead of just having the last a fly over?
Is this for a class, or are you asking a serious question?
For each class of college, the answer is if two balls down, two pop up. It conserves energy and momentum
If you just ask your own interest, you raise a good point. It is possible to conserve both momentum and energy and have a different result, then is typical with Newton's cradle. You could have a ball will fly high and two or more balls go slightly forward.
The reason why Newton's cradle works is not the conservation of momentum and energy, but the compression of the balls and the propagation of sound waves in the balls. The sound waves act as if you hit once the cradle and then you hit again, causing First One Ball, their milli-fraction of a second later, the second ball must be blown out of the end.
This is not just energy that is retained is the momentum too.
Posted on June 28, 2010.
