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Power problem

  1. Oct 26, 2014 #1
    1. "A car moves along a horizontal road against a resistance of 400 N. What is the greatest speed in kph that the car can reach if the engine has a maximum power of 16.0 kW?"


    2. Relevant equations:
    P= W/change in time
    P= F x v (dot product)
    Please help ):
     
    Last edited: Oct 26, 2014
  2. jcsd
  3. Oct 26, 2014 #2

    NascentOxygen

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    Staff: Mentor

    W = F x v
    is not correct

    x is not the sign for a dot product
    x is the cross product
     
  4. Oct 26, 2014 #3
    Sorry didn't know how to put the dot symbol that's why I put it in parentheses whoops
     
  5. Oct 26, 2014 #4

    NTW

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    Besides, work is not force times velocity...
     
  6. Oct 26, 2014 #5

    NascentOxygen

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    Staff: Mentor

    The symbol mistake was incidental. The major problem is your formula W = F v
    is not a valid formula. What formula for work does your textbook use?
     
  7. Oct 26, 2014 #6
    Edited: it's power=fv.
     
  8. Oct 26, 2014 #7
    Edited, p=fv
     
  9. Oct 26, 2014 #8

    NascentOxygen

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    Staff: Mentor

    So, can you use that equation to determine the "greatest speed" as the problem statement asks?
     
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