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Homework Help: Find Acceleration Experimentally

  1. Oct 8, 2009 #1
    You drop an object. You take the time it takes to hit the ground. So you have Δx (displacement) and time.

    To find acceleration do you use

    xf= xi + Vi t + .5at2
    Δ x= Vi t + .5at2
    Δ x- Vi t=.5at2
    a= 2(Δ x- Vit )/ t2

    or do you use

    v= Δ x/ Δ t
    a= Δ v/ Δ t

    Should acceleration come out the same? Why do they differ so much? Take example a Δx of 2m and a time of .5. Using the first equation you get 16 m/s^2. But using the second method, you get 8 m/s^2.
  2. jcsd
  3. Oct 8, 2009 #2
    It seems to me that you're not given enough information. If you had the initial and final velocity, you could plug into

    [tex] V_{f} = V_{i} + at[/tex]

    to experimentally find the acceleration.

    What would be easier is to use newton's second law (F=ma) since then you only need to know the object's mass and the force it exerts on the ground upon impact to experimentally determine the value of g.
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