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Homework Help: Vector question

  1. Nov 4, 2012 #1
    1. The problem statement, all variables and given/known data
    A swimmer heads across a river flowing at 7km/h.
    Her speed relative to the water is 8km/h.
    The river is 362m wide.
    There are other questions; however, I just need help with the diagram.

    2. Relevant equations

    3. The attempt at a solution
    I'm not too sure on how to draw the diagram- I made a right angle triangle with the bank as shown in the picture. Is this correct?

    Attached Files:

  2. jcsd
  3. Nov 4, 2012 #2
    Not quite.

    The river is flowing (right) at 7km/hr
    The swimmer moves (diagonally) at 8km/hr

    So you can calculate how fast the swimmer is moving directly across the river by drawing a triangle of velocities.

    Once you've got the speed it's easy.
  4. Nov 4, 2012 #3
    Oh I see what you mean, i wasn't sure if relative to implied it was the true course. Thank you.
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