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2D motion problem

  1. Mar 29, 2008 #1
    1. The problem statement, all variables and given/known data
    A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 8.40m/s at an angle of 17° below the horizontal. It stikes the ground 4.00 s later.

    a. How far horizontally from the base of the building does the ball strike the ground?
    b. Find the height from which the ball was thrown
    c. How long does it take the ball to reach a point 10.0 m below the level of launching?

    2. Relevant equations

    3. The attempt at a solution

    I don't understand how it can be 17° below the horizonal axis. If it is below the x axis, doesn't that mean that it is negative? Would I just use cos and sin for parts a and b? Could someone please give me a hint on part c?

    Thank you very much
  2. jcsd
  3. Mar 29, 2008 #2
    It's not impossible to throw a ball downwards from a building. You have a velocity, time, and you have the angle to the horizontal. Remember, break projectile motion problems into x and y situations.
  4. Mar 30, 2008 #3
    Thank you very much

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