1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Error propagation

  1. Jan 28, 2015 #1
    1. The problem statement, all variables and given/known data
    suppose i measure the time t for 20 oscillations fro a pendulum. the period is T.

    2. Relevant equations
    Since T = t / 20
    delta T = delta t right?

    3. The attempt at a solution
    since the 20 is a numerical value, it does not come in the error propagation, does not? when i used the above equation, i can't get the required answer but when i divide by 20, the answer is obtained.

    can someone explain why?
     
  2. jcsd
  3. Jan 28, 2015 #2

    Nathanael

    User Avatar
    Homework Helper

    T is what you measure the period to be, right? (T = t / 20) So the true period will be T+ΔT where ΔT is some error.

    The true time it takes for 20 oscillations is 20(T+ΔT), which equals the time you measured plus some error Δt

    [itex]20(T+ΔT)=t+Δt[/itex]

    So if [itex]20T=t[/itex] then:

    [itex]20ΔT=Δt[/itex] ... or ... [itex]ΔT=\frac{Δt}{20}[/itex]
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted