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Homework Help: Speed problem

  1. Oct 28, 2007 #1
    A 10,500kg railroad car travels alone on a level, frictionless track with a constant speed of 15.0 m/s. An additional 5,000kg load is dropped from a tower onto the car. What will then be its new speed?



    2. Relevant equations

    Momentum of conservation: m1i+m2i=(m1+m2)vf





    3. The attempt at a solution

    Plugging in the numbers i get:

    10,500kg(15m/s) + 0 = (10,500 kg+5000 kg)vf

    157500kgm/s+0=(15,500kg)vf
    10.16 m/s=vf
    vf=10.2m/s

    is this correct?
     
  2. jcsd
  3. Oct 28, 2007 #2

    G01

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    Homework Helper
    Gold Member

    Looks good to me.
     
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