Conservation of momentum and springs

  • Thread starter EMUGOD
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  • #1
I apologize if this is a silly question, but i swear it is not a homework assignment (or, it may be to someone somewhere, but that is no the reason i am interested in it).

If you have a number of pins suspended through vertical platters such that they just touch, they will exhibit the behavior of a newtons cradle, correct? In terms of intermediary pins remaining stationary and the energy just passing through them?

If so, what affect will springs have on the system? I have included a diagram of what i think the situation will be but am not sure. will the intermediary pins still remain stationary, with the final pin being pushed out? And the combined force of the springs will be lost from the overall force at the end of the system?

I am trying to develop a way to pass this energy through a series of selective plates. At first i was considering just making the originator pin long enough to reach through and having the plates block it, but i fear that will result in damage or very rapid wear. Instead i am thinking of this system, where a lack of a proceeding pin will break the connection. Again i apologize if this is not the intention of this forum.


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  • #2
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I don't think that putting the springs in will simulate the Newton's cradle behavior. A similar situation was discussed here. The gist of it is this: When there is an infinitesimally small gap between the colliding objects, the transfer of energy is instantaneous so one mass comes to rest and the other acquires all the energy. If you put in springs, they will store some of the energy as they stretch and compress and the system will act more like a collection of coupled oscillators than Newton's cradle.