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Homework Help: Conservative of momentum

  1. Jun 21, 2010 #1
    1 car has mass 15000 drive in velocity 40m/s and 1 van has mass 30000 drive in velocity 30m/s after collision the car go back 3m/s so what is the velocity of the van if the car and the van drive in 1 direction on the street?... i really doubt if the velocity of car is -3m/s



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jun 21, 2010 #2

    Doc Al

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    Staff: Mentor

    If I understand you correctly, the problem statement tells you that the car bounces back at 3 m/s (and thus its velocity is -3 m/s). Use that fact to calculate the speed of the van after the collision.
     
  4. Jun 21, 2010 #3
    but i still dont know why the car hit the van in the speed of 1 direction and the result the car bounce back 3m/s it not logic
     
  5. Jun 21, 2010 #4

    Doc Al

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    Staff: Mentor

    It's certainly not realistic data. Perhaps you are misinterpreting what was meant:

    Perhaps that means the speed of the car was reduced by 3 m/s. That would be much more realistic.

    Did you provide the problem exactly as it was given to you, word for word? If not, try to do so.
     
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