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Homework Help: Relative Velocity Problem

  1. Oct 4, 2008 #1
    A swimmer heads directly across a river, swimming at 1.6m/s relative to the water. She arrives at a point 40m downstream from the point directly across the river, which is 80m wide.

    A) What is the speed of the river current?
    B)What is the swimmer's speed relative to the shore?
    C)In what direction should the swimmer head in order to arrive at the point directly opposite her starting point?

    Can someone guide me in a starting point? I am really confused on the whole "relative velocity" topic. All those "relative" to this and to that gets me confused.
    Can someone help me break down what the problem really is saying?
  2. jcsd
  3. Oct 5, 2008 #2


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    Part A is similar to projectile motion. You need to take components of motion. You know the swimmers velocity across the river and can work out how fast it would take to reach the other side if the river was still. Then you can work out how fast the river must move to sweep her forty metres off course in the same time.
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