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Error analysis, multiplying an error

  1. Nov 9, 2011 #1
    Equation: M (ΔT)=
    The question:
    If ΔT has an error of one degree, and i multiply it by the mass of an object (m) is the error in y still one

    Attempted answer: or is it proportional to M i.e Δt plus or minus 1 degrees so the error in y is 2M?

    P.S i need to be able to know the error for a whole bunch of values because im putting m delta t as an axis on a graph, would i have to work it out for each value of m ΔT
  2. jcsd
  3. Nov 9, 2011 #2
    Hi welcome to physicsforums. :smile:

    I suppose that with "degree", you mean degree Celcius. If you multiply with a constant (thus the constant has no or negligible error) then the percentual error remains the same.

    You can find that answer yourself simply by trying:

    Last edited: Nov 9, 2011
  4. Nov 9, 2011 #3


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    generally speaking, if you have an error in x then the error in y will be the derivative of the function used on x times the error in x. for a straight line, the derivative is a constant value, thus the error in y is a constant value times the error in x.
  5. Nov 12, 2011 #4
    yeah thanks harrylin thats exactly what i was trying to figure out, much appreciated
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