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!

Homework Help: Expressing one Vector in terms of others

  1. Oct 30, 2016 #1
    1. The problem statement, all variables and given/known data 6pvAr0Q.jpg

    I am very rusty on my mathematics and I am wondering if there is a way to express Rs in terms of r1 and r2. The positions of the bodies are all relative to the origin 0 (C.o.M between m1 and m2). Basically I'm trying to express the two vectors coming from m3 in terms of the masses and position vectors for m1 and m2.

    2. Relevant equations

    3-1 = r1-Rs
    R3-2 = r2-Rs

    3. The attempt at a solution

    I think r1 and r2 are related through the expression: r2= -(m1/m2)*r1 but this was very much 'fudged' so I think I'm approaching the problem wrong.

    Any help much appreciated.
  2. jcsd
  3. Oct 30, 2016 #2
    Clearly, r1, r2 are linearly dependent and span a 1-D space. Rs can never be an linearly combination of them. I think it would be more natural if you define that "r1-Rs" vector to be r1 and "r2-Rs" to be r2.
  4. Oct 31, 2016 #3


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes, use that, so you can express both positions in terms of Rs and r1.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted