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Homework Help: Velocity in two dimensions

  1. Oct 21, 2009 #1
    A glass is slid across a table top, goes off the edge and falls to the floor. The table is 0.860m high and the glass lands 1.53m from the edge.
    a)With what velocity did the glass leave the table top?
    b)What was the direction of the glass's velocity(degrees clockwise from the horizontal)as it hit the ground?

    For a) I believe that I have to find the x component of velocity.

    xf=xi+vxit+.5axt^2 But I dont know the time either!

    b) tan(0.860/1.53)= 29.3degrees
  2. jcsd
  3. Oct 21, 2009 #2


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    Hi waldvocm! :smile:

    (try using the X2 tag just above the Reply box :wink:)

    For a), call the time t, and do two equations, one for x and one for y. Then eliminate t.

    What do you get? :smile:
  4. Oct 21, 2009 #3
    I am not sure that I follow. Do you mean a quadratic equation?
  5. Oct 21, 2009 #4
    How can I find the time if I don't know the velocity?
  6. Oct 21, 2009 #5


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    Call the velocity v, call the time t, get two equations which both contain v and t.

    That's two equations with two unknowns, so you should be able to find both of them.
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