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Projectiles launched horizontally

  1. Oct 10, 2006 #1
    okay so heres the problem..

    the fastest recored pitch in MLB was thrown by nolan ryan in 1974. if this pitch were thrown horizontally, the ball would fall 0.809 m by the time it reached the home plate, 18.3 m away. how fast was this pitch?

    the book suggests the equation
    delta y = -1/2g(deltat)squared

    we just started this lesson and i'm really not sure what variable represents what in this problem :confused:
     
  2. jcsd
  3. Oct 10, 2006 #2

    Hootenanny

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    If you simply want to know how to use the formula, then the variables are as follows;

    y is the vertical displacement
    g is the acceleration due to gravity
    Δt is the time of flight
     
  4. Oct 10, 2006 #3
    well, would it be .809=-1/2(g)(t)squared, what else are you supposed to do with this? like where does the horizontal displacement go
     
  5. Oct 10, 2006 #4

    Hootenanny

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    That's right. You now need to solve for the time of flight t. You can then use this together with the horizontal displacement to find the initial velocity.
     
  6. Oct 10, 2006 #5
    ahh im completely lost now i tried to isolate teh unknwon (t) from the rest of the problem and got t= the square root of 2(delta y)/-g

    but the book says that is only for when delta y is negative. can someone explian this problem to me step by step? im reallly confused.
     
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