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: Significant figures experiment

  1. Nov 19, 2008 #1
    Hi just a quick question about sig figs. If one was too divide a time such as 21.76s into increments of twenty to find the period of revolution for a centripetal force experiment would the answer be two or four significant figures? also if I multiply a mass such as 2567kg by acceleration due to gravity should my final answer be two significant figures? I am sure the answer to my second question is yes but the first I am not so sure about.
  2. jcsd
  3. Nov 19, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    21.76 is 4 sig figures. If you measured say 20 rotations to get this answer then yes, you know the time of one rotation to 4sig figures.

    If you have a mass of 2567kg (again to 4 sig fig) and divide by g=9.81 then you only have 3sig figures in you answer. Or more correctly you have mass of 2567 +- 0.5kg and g=9.81 +- 0.005 so you know g to 1 part in 2000 you would know your answer to 1 part in 2000, ie approx +- 1kg.
    If you used g=9.7 then you have only 2sig figures and an error of 1 part in 100.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook