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help (: adding vectors! components... angles, drawing.

  1. Jul 9, 2017 #1
    1. The problem statement, all variables and given/known data
    A ship travelling 55 degrees [W of N] is 65km farther north after 3.0h. What is the ship's velocity.

    2. Relevant equations
    sin, cos, tan?

    3. The attempt at a solution
    I know that Vground= Vair + Vwind, and that Vground = Vboat + Vcurrent, but i'm not sure if that is even relevant to the question... So far I have drawn out :

    Do I add these vectors together or subtract? and am I trying to find the boat's velocity or ground velocity. I think boat velocity but what does that make of the 55 degrees W of N... I am so lost please help (:

    Screen Shot 2017-07-09 at 7.48.31 PM.png
     
    Last edited: Jul 9, 2017
  2. jcsd
  3. Jul 9, 2017 #2
    You need to show some attempt at a solution first before others will try to help you.
    Try drawing out the problem at least.
     
  4. Jul 9, 2017 #3
    Ok! ive never used this before lol so I don't know what I'm doing. But thanks, I will do that.
     
  5. Jul 9, 2017 #4

    gneill

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    Staff: Mentor

    Your image link appears to be addressing a target that is not publicly accessible. I suggest that you UPLOAD the image file to the PF server so that it's made available t our homework helpers (use the UPLOAD button).
     
  6. Jul 9, 2017 #5
    Thank you!!!
     
  7. Jul 9, 2017 #6

    gneill

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    Staff: Mentor

    On your image you've labelled the distances x and y. y is the distance that the boat traveled in the northward direction, and presumably x is distance it traveled in the westward direction. Can you determine the total distance it traveled along its trajectory? (hint: what's the length of the hypotenuse of that triangle?)
     
  8. Jul 9, 2017 #7
    Now im not sure... Do I use v=d/t. The answer in the book says its 38km/h but that doesn't seem to match up with my numbers.
     

    Attached Files:

  9. Jul 9, 2017 #8

    gneill

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    Staff: Mentor

    Your evaluation of c doesn't look right. Please show your calculation in detail. What is a? What is b?
     
  10. Jul 9, 2017 #9
    Oops I see where I made a mistake.. instead of putting a as 65 squared, I put 95 squared. Just a calculation error! Thanks for your help, I've figured out the question now (:
     
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