1. when I have systems with 3 mass points ($m_i, i=1,2,3$) to a time $t=t_0$ on positions $\vec r_i(t_0)$ and velocity $\vec v_i(t_0)$. How could a syntax look like to calculate

1) center of mass 2) total momentum 3) total angular momentum

for any number of mass points?

  1. Secondly, later when time is $t_1 > t_0$ the positions and velocities of 2 of this 3 mass poins are known. How could mathematica calculate position and velocity of third mass point, when there is no external force ?

Thank you very much!


Center of mass:

Total[m1 r1, m2 r2, m3 r3]/Total[m1,m2,m3]

Total momentum:

Total[m1 v1, m2 v2, m3 v3]

Total angular momentum:

Total[m1 Cross[r1,v1], m2 Cross[r2,v2], m3 Cross[r3,v3]]
  • $\begingroup$ thanx so far david! $\endgroup$ – Tom Jan 12 at 20:44

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.