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Homework Help: Quick Question, no solving required

  1. Feb 17, 2008 #1
    [SOLVED] Quick Question, no solving required

    Jason hits a volleyball so that it moves with an initial velocity of 6.0m/s straight upward. If the volleyball starts from 2.0m above the floor, how long will it be in the air before it strikes the floor? Assume that Jason is the last player to touch the ball before it hits the floor.

    Why does this problem have a final velocity ? The final velocity when going to highest distance is 0, and when it is on the ground again, it's final velocity is also 0, then according to my book, why does this ball have a final velocity?
  2. jcsd
  3. Feb 17, 2008 #2
    the final velocity required is most likely the velocity just of the ball just as it hits the floor. Perhaps your text did not word this very well.
  4. Feb 17, 2008 #3
    it will have a final velocity right before it hits the ground, but when it actually hits the ground again it will be 0. Generally, questions want to know right before it hits again. You can solve for this by using only half of the total motion, by starting with v=0 at the top as you said and using half the distance( aka same as total height) to solve for the final velocity.
  5. Feb 17, 2008 #4

    This assumption is correct. With regards to projectile motion, when the object strikes the ground, Vf is not zero, it is its velocity at the instant before it strikes. After that, it is outside the realm of projectile motion.

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