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Homework Help: Launch velocity of the projectile

  1. Feb 19, 2010 #1
    1. The problem statement, all variables and given/known data
    A projectile is launched in such a way as to have a time of flight of 41s and a range of 11 750m.
    Calculate:
    a) the maximum height reached;
    b) the launch velocity of the projectile.


    2. Relevant equations
    h=ut-1/2gt^2


    3. The attempt at a solution
    h=-1/2gt^2
    -1/2 * 9.8 * 41^2

    I don't get the answer.
     
  2. jcsd
  3. Feb 19, 2010 #2

    ideasrule

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    Re: Vectors

    You wrote h=ut-1/2gt^2 but used h=-1/2gt^2, even though u is not 0.
     
  4. Feb 19, 2010 #3

    Andrew Mason

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    Science Advisor
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    Re: Vectors

    What is the formula for vertical velocity? What is it at maximum height? That will give you the initial vertical velocity. From that, you can use your formula to find maximum height (Hint: what is t at maximum height?).

    What is the horizontal velocity?

    You can then find the launch velocity (direction and speed) from the horizontal and vertical velocity.

    AM
     
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