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Homework Help: Mirror reflection. PLS help

  1. Apr 29, 2007 #1
    1. The problem statement, all variables and given/known data
    1. Dubbie is moving directly along a normal line toward a plain mirror at a speed of 3.5 m/s, what is the speed of the image relative to Dubbie?
    2. What is the speed of the image, relative to Dubbie, if Dubbie walk away from the mirror surface at 3.5 m/s at an angle of 300 to the mirror surface

    2. Relevant equations

    Do = Di

    3. The attempt at a solution

    I think that both of the answers are 3.5 m/s. Except im pretty sure that the 30 degree in the 2nd question will change something somehow, but i'm not sure which equation to use...
  2. jcsd
  3. Apr 29, 2007 #2


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    Gold Member

    1. If two thing move towards a single point between them, with velocities v and -v, what is their relative velocity ?

    2. You'll have to draw a triangle and solve this by trigonometry.

    3. Your efforts so far are not impressive. Try to draw a diagram, and imagine the situation as if it were a movie.
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