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Physics lab, calculating/combining errors

  1. Sep 15, 2010 #1
    I just started the semester off in physics lab and I am so rusty. I did three perfectly okay by myself but these last three I can't seem to figure out. Any help on the direction to take with these is appreciated!

    c) T = 0.433 ± 0.004 s. Calculate T^2 andΔT^2.

    d) Given d = vt, v = 55 mi/hr ± 5% and t = 5.00± 0.03 hrs, calculate d and Δd.
    Like here do I put in d= (55 ± 5%)(5.00 ± 0.03)
    I know I have to get the percent into an actually number, I can do that. but I dont know if this is the way to go about it and then I really dont know how to get Δd.

    e) Given a = 2d/ t2 , d = 82.0 ± 0.2 cm and t = 4.23 ± 0.05 s, calculate a and Δa.
     
  2. jcsd
  3. Sep 15, 2010 #2
    Hint:

    C) If X = a ± b then ΔX ^ n = X ^ n * ( n * ( ΔX / X ) ) = a ^ n ( n * (b / a ) )

    D) Δd = Δ(vt) = vt ( ΔV / V + Δt / t )

    E) Δ(2d/t^2) = 2d/t^2 ( Δd/d + Δt^2/t^2)
     
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