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Homework Help: Newton Law Concept Question

  1. Oct 9, 2008 #1
    1. The problem statement, all variables and given/known data
    Two boxes full of books are in contact with each other on a smooth table. Box H has twice the mass of Box G. If you push on box G with a horizontal force F, then box H will expereince a net force of?

    2. Relevant equations

    F =ma

    3. The attempt at a solution
    answer from answer key is 2/3F

    I though since the mass of H is twice of G, the F needed will be 2F... but I am wrong.. Please help with the question! Thank You
  2. jcsd
  3. Oct 9, 2008 #2
    First you need to find the acceleration of both blocks combined. If you call box H = 2G then you can write an equation F= (G + 2G) a.

    Solve this for a = F/3G. Now consider the net force on box H to make it accelerate with an acceleration of F/3G. FH = 2G * F/3G
    Last edited by a moderator: Oct 9, 2008
  4. Oct 9, 2008 #3
    Thank You so much!!! You are very helpful!
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