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Homework Help: Crossing a River

  1. Jan 25, 2005 #1
    A swimmier heads across a river, swimming at 1.20m/s relative to still water. It arrives at a point 67.0 m downstream from the oint directly across the river, which is 100.m wide. What is the speed of the river current?

    Here's what I did:

    theta = 33.82 degrees

    Vx = Vxocos(33.82)
    Vx = 1.20m/s * cos(33.82)
    Vx = 0.997m/s

    and since the current is moving in the opposite direction it would be -0.997m/s.

    Does that sound about right?
  2. jcsd
  3. Jan 25, 2005 #2
    it's wrong.

    So obviously my method of getting the answer was flawed aswell. Is there another way to solve this problem?
  4. Jan 25, 2005 #3
    Determine the time it takes to cross the river. In this period the swimmer drifts 67 m. Solve for the current speed.
  5. Jan 25, 2005 #4


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    Homework Helper

    1.20 m/s is the speed of the swimmer in still water. Not his total speed. His velocity is 1.20 m/s in the x-direction (direction across river), and v in the y-direction(along the river), where v is the river speed. How long does it take him to cross the river?
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