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Homework Help: Theoretical Line

  1. Sep 28, 2006 #1
    I have a lab question that states "does your experimental value agree with the theoretical line for projectile motion?" What is a theoretical line and how do I compare these value.

    I thought a theoretical line is x=V(sq.root(2h/g)), but im not sure.
     
  2. jcsd
  3. Sep 28, 2006 #2

    radou

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    What value did you measure?
     
  4. Sep 28, 2006 #3
    i measured the horizontal distance and and horizontal velocity.
     
  5. Sep 28, 2006 #4

    radou

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    So, which is the equation of the displacement in the x-direction? Which is the equation of the horizontal component of velocity? Use these equations to compare your test results with the 'theoretical' values.
     
  6. Sep 28, 2006 #5
    The problem is that the theoretical values are not given. All I have is the equation and a plot of my experimental values. How do I determine the theoretical line that I need to compare my values?
     
  7. Sep 28, 2006 #6

    radou

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    Well, I guess you have a plot of your experimental values dependent on time, right? So, just plug the 'times' into the 'theoretical' equations and compare the results. I hope I'm not missing something big here.
     
  8. Sep 28, 2006 #7
    It is not a plot dependent on time. The plot is x (distance) vs. horizontal velocity. I plugged the values into the equation above and compared the values. But, is there a way I can draw or determine the theoretical line?
     
  9. Sep 28, 2006 #8

    radou

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    Horizontal velocity is constant and equals vx = v0*cosA, where v0 is the initial velocity and A is its angle. Since it is constant during time, it is represented as a horizontal line in a t-vx coordinate system. Maybe this is what you mean by 'theoretical' line.
     
  10. Sep 28, 2006 #9
    how is it represented in a X vs Vx coordinate system?
     
  11. Sep 28, 2006 #10

    radou

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    The same. vx is constant for every point x.
     
  12. Sep 28, 2006 #11
    hmm.. i think i got it thanks
     
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