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Homework Help: What impulse is needed to change the speed of a 16 kg object

  1. Dec 10, 2003 #1

    Dil

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    This question is infuriating me. It says the answer is 32, but I can't get that.
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    What impulse is needed to change the speed of a 16 kg object from 14 m/s to 26 m/s in a time of 5s? How much force is needed?

    mVf - mVi
    (16)(26)-(16)(14) = 192

    F(change in 5s)=192 192/5 = 38.4N
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    What am I doing wrong?
     
  2. jcsd
  3. Dec 10, 2003 #2
    Impulse is a vector quantity and speed a scalar. Is the direction changing pls see it
     
  4. Dec 10, 2003 #3

    Dil

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    I don't think the direction is changing
     
  5. Dec 11, 2003 #4
    Perhaps the given answer is wrong... It sure looks wrong to me!
     
  6. Dec 11, 2003 #5
    Yes to me it 2 seems to be on wrong side
    thats why i asked for direction
     
  7. Dec 11, 2003 #6

    NateTG

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    Science Advisor
    Homework Helper

    You sure it's not 16 to 26 m/s or 14 to 24 m/s?
     
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