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Homework Help: I need help in verticle motion

  1. May 5, 2005 #1
    child play with cubes , he threw first one vertically to up with velocity of (v), after five seconds he threw second cube vertically to up with the same velocity , two cubes collided at 9 meter height what the velocity of two cube? (they are the same!)

    actually i dont know but final answer, i need help please

    and thank you all again , again , and again :tongue: .
  2. jcsd
  3. May 5, 2005 #2
    You want to use [tex]s = ut + \frac{1}{2}at^2[/tex] and [tex]v^2 = u^2 + 2as[/tex] setting s to 9 each time. Then the two equal each other and you can find a time as you know the acceleration and the time in each case.

    The Bob (2004 ©)
    Last edited: May 5, 2005
  4. May 5, 2005 #3


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    You should write the equation of motion in vector form

    [tex] \vec{r}(t)=\vec{r}_{0}+\vec{v}_{0}t+\frac{1}{2}\vec{a}t^{2} [/tex]

    and then choose an axis along which the movement takes place,an origin for this axis, then a sense on this axis and then do the projection of the vector equality on this axis...

    This is just the beginning,but it's essential.

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