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When were the boats closest to each other?

  1. Mar 29, 2009 #1
    1. The problem statement, all variables and given/known data
    A boat leave a dock at noon and heads weat at a speed 25km/h. Another boat heads north at 20km/h and reaches the same dock at 1:00 pm. when were the boats closest to each other?


    2. Relevant equations
    when were the boats closest to each other?



    3. The attempt at a solution
    I use the pythagorean for the distance
    but I'm not sure about how to sub them in?
    I tried to assume that the second boat also leaves at noon, so the total distance will be 20km. But thats wrong. Please help, thanks =P
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 29, 2009 #2
    First, I think you have to find the rate of change of the hypotenuse.
     
  4. Mar 29, 2009 #3

    tiny-tim

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    Science Advisor
    Homework Helper

    Hi zapped! :smile:
    No, that assumption is fine (not necessary, but fine).

    Anyway, minimising the pythagorean, which is what you tried to do, should have worked …

    show us what you got for the pythagorean :smile:
     
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