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Homework Help: Physics 12 help for homework

  1. Jul 4, 2009 #1
    1. The problem statement, all variables and given/known data

    A golfer is a putting on a green, and takes 3 strokes to "hole the ball" On the first putt the ball rolls 5.0m due east. The second putt travels 2.1 m at an angle of 20.0 degrees north of east. The third putt is 0.50m due north. What displacement (magnitude and direction relative to due east) would have been needed to "hole the ball" on the very first putt?

    2. Relevant equations

    R^2 = A^2 + B^2 - 2ab COS(angle)

    3. The attempt at a solution

    I drew them out. I have troubles finding the displacement with 3 directions given.
  2. jcsd
  3. Jul 4, 2009 #2


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    Homework Helper

    Welcome to PF.

    In problems like this I find it a little easier to separate them into x,y components and then sum the components.

    So for your problem taking East as positive x ...

    P1 = 5 x + 0y
    P2 = 2.1*cos20 x + 2.1*sin20 y
    P3 = 0 x + .5 y

    Your resultant then is the sum of the 3 P vectors right? And your answers are precise. Easy peasy, nice and easy.
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