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Homework Help: Tricky Kinematics Problems - Desperately need help!

  1. Oct 14, 2008 #1
    1. The problem statement, all variables and given/known data
    I am new to this board, but I am at my wits end trying to solve this problem. If anyone could provide a somewhat detailed solution i would forever be in debt, thanks!

    One car, located at position (-29.9 , 0 ) is travelling at 12.7 m/s ( +x)
    Another Car, located at position ( 0, -41.0) is travelling at 6.5 m/s ( +y)

    +y Direction
    ^
    |
    |
    ----------> + x direction

    Calculate the smallest distance between the two cars

    2. Relevant equations

    I created two functions :
    p1 (t) = 12.7t - 29.9
    p2 (t) = 6.5t - 41.0

    Which represent the position of the cars, based on time, relative to the origin




    3. The attempt at a solution

    Using pythagorean theorom, i concluded the distance between them can be summarized as

    d^2 = (p1(t))^2 + (p2(t))^2

    Then i Attempt to solve the minumum of this function, which is where i always screw up.

    The correct answer to the problem is 22.9 m
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Oct 14, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi RPierre! Welcome to PF! :smile:
    Well, that's fine so far. :smile:

    Show us how you tried to solve it, and then we'll be able to see where the problem is. :wink:
     
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