Conservation of energy and momentum governs Newton cradle. If $n$ balls were lifted, $n$ balls will bounce of on the other side. This happens if all balls have the same mass. Now, assume that you have a cradle with balls $a,b,c,d,e,f.$ All balls except $f$ has weight 1. Ball $f$ has mass $n+0.5$ (1.5 or 2.5). We lift ball $f$ and bring it to motion. What will happen on the other side?

I would guess that n balls would fly to the original height and one more ball will fly half way.


As far as I can tell physicists never tried this experiment fearing it will destroy the Universe. :-)

The so called duplicate is NOT a duplicate because it talks about integer mass ratios, whereas I ask about fractional mass ratios. Also, that answer provides a link to a single clip about a single case. that doesn't answer anything. Besides, even if that question was related, there is no way for me to revitaliate it.


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    $\begingroup$ Possible duplicate : Experimental data for asymmetric Newton cradle $\endgroup$ Oct 7, 2016 at 18:49
  • $\begingroup$ The answer is "we don't know, but we provide you with a free downvotes". The "possible duplicate" is irrelevant. It talks about (1) Integer mass ratios, while I ask about fractional case (2) The upvoted answer boils down to "I don't know and there imperfection in apparatus and there are no experimental clips, only the animation". $\endgroup$
    – Stepan
    Oct 12, 2016 at 13:13
  • $\begingroup$ Stepan : I am sorry that your question has been closed. The down-vote is mine because I felt that you had not made a reasonable effort to calculate or research an answer. You mention conservation of energy and momentum. Can you apply these to confirm that your "guess" is correct? $\endgroup$ Oct 12, 2016 at 17:04
  • $\begingroup$ @sammygerbil No problem. Phisics.SE exists for downvotes and closing questions, not answering them. You did the right thing. I am not a physicist to solve Lagrangian. Thanks for a warm welcoming from your awesome community. $\endgroup$
    – Stepan
    Oct 12, 2016 at 17:10
  • $\begingroup$ If you feel that your question is different from the other one, you should edit it to point out in what way, and why my answer does not satisfy you. Edits cause your question to be reviewed, but comments do not. I will vote to reopen your question, and remove the down-vote, after your update. Newton's Cradle looks simple, but the fact that it is still being researched shows that it is not fully understood. $\endgroup$ Oct 12, 2016 at 20:06


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