1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

System from three bodies

  1. Jul 5, 2015 #1
    The figure shows a system consisting of two identical spheres of mass m and a mobile platform mass M. If the system starts from rest in the position shown in the figure, what is the speed from each sphere in the moment when both move horizontally, before the crash occurs. Neglect all friction.
     

    Attached Files:

    • 8.jpg
      8.jpg
      File size:
      6.7 KB
      Views:
      96
  2. jcsd
  3. Jul 5, 2015 #2

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    This looks lie a homework type question. Easy(ish) to solve if you remember that the PE at the start becomes KE at the end.
     
  4. Jul 5, 2015 #3
    Its not easy. Please try it to solve
     
  5. Jul 5, 2015 #4

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    I will have a go this evening if time permits. Is it really not just the conservation laws that solve it? (Momentum too)
     
  6. Jul 5, 2015 #5
    NO
    more equation is needed
     
  7. Jul 5, 2015 #6
    What else equations? It is obvious that Newtonion physics is sufficient... you have not even friction!
     
  8. Jul 5, 2015 #7
    Conservation of momentum on the x axis and conservation of energy (2 equations but three unknown speeds)
     
  9. Jul 5, 2015 #8

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    Yep. Fair enough. Another equation is needed too.
     
  10. Jul 8, 2015 #9
    Can you help me sophiecentaur?
     
  11. Jul 8, 2015 #10
    Someone who can help me in this challenge problem?
     
  12. Jul 9, 2015 #11

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    Sorry about this but it requires a lot of time, I think. Afaics, you would need to write out the equation of motion, from t = 0, for all three bodies and arrive at an integral which has to be solved. To make it harder, the limits for the short fall will be different from the long fall.
    BTW, who has set you this beastly problem? Perhaps you could go back and ask for guidance??? After all, they really should be able to help - if they have actually realised how hard the problem appears to be. Is it a a level that's appropriate to the level of the course you're following?
     
  13. Jul 11, 2015 #12
    This problem I have created myself. Who do you think could help me?
     
  14. Jul 12, 2015 #13

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    If it your own problem then perhaps you should start from the beginning, with a simpler situation and work up to your OP.
    Start with a single ball on a linear slope, then a single ball on a circular slope.
    PF has had a number of threads about blocks on inclined planes (fixed and sliding), to give you a start with finding the sort of approach needed.
     
  15. Jul 13, 2015 #14
    AlreadyI did it. Only I wish to know the opinion of a specialist.
    Could you propose this problem on other forum please. I can`t believe that nobody can propuse a solution.
    Thanks
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: System from three bodies
  1. Three-body problem (Replies: 7)

  2. Three-Body Problem (Replies: 10)

Loading...