1. Not finding help here? Sign up for a free 30min 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!

Center of mass particle problem

  1. Dec 9, 2003 #1
    A 4.01g particle is moving at 1.36 m/s toward a stationary 9.43g particle. With what speed does the heavier particle approach the center of mass of the two partciles?

    i dont get how cm relates to finding speed

    The mass of a star like our sun is 347000 Earth masses, and the mean distance from the center of this star to the center of a planet like our Earth is 6.63*10^8 km. Treating this planet and start as particles, with each mass concentrated at its respective geometric center, how far from the center of the star is the center of mass of the planet-star system? Answer in units of km.
  2. jcsd
  3. Dec 9, 2003 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Well, how do you find the center of mass of a two particle system?
  4. Dec 9, 2003 #3
    is it like V_cm = m1v1+m2v2 / m1 + m2?
  5. Dec 9, 2003 #4


    User Avatar
    Science Advisor
    Homework Helper

    You probably meant
    [tex]V_{cm}=\frac{m_1v_1+m_2v_2}{m_1+m_2}[/tex] which is correct. You should be carefull to put your parens in where necessary.
  6. Dec 9, 2003 #5
    thx nate..
    i have one more question for that first problem.

    how would you calculate the magnitude of momentum of the lighter particle relative to the center of mass?
  7. Dec 9, 2003 #6


    User Avatar
    Science Advisor
    Homework Helper

    Linear momentum is mv.
    Since you know the mass already, so all you have to do is figure out the relative velocity.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Center of mass particle problem