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Homework Help: Physics question

  1. Jan 23, 2008 #1
    A boy is swimming a river with a width of 65m. He is swimming from one side to the other at a constant speed of 2.3 m/s, and the current, parallel to the bank is moving at 1.1 m/s. How long will it take him to cross the river, and what will the angles be between his final path and the river bank be?
  2. jcsd
  3. Jan 23, 2008 #2
    You really should show a little more work, but just to prompt you:

    You have two perpendicular vectors. One has magnitude 1.1, the other has magnitude 2.3

    The resultant vector will be the actual path he follows and the resultant vector magnitude will be the actual speed he travels along that actual path

    So how do you
    A)Draw this? You can draw two perpendicular vectors of course, what does the resultant look like relative to those two?
    B)Find the magnitude of the resultant vector?
    C)Find the angle between the resultant vector and, in this case, the vector running parallel to the river bank?
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