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: Metric problem

  1. Sep 11, 2007 #1
    1. Is it advantageous that fundamental standards, such as those for length and time, be accessible, invariable, indestructible, and reproducible. Disscuss why these are advantages and whether any of thse criteria can be incompatible with others.

    I don't understand what it's asking.

    I think it is advantageous because we won't have to worry about constantly changing our system to adapt to the new one. So, people all over the world can convert from one number to another through the metric system.

    2. Why is 516m (1693ft) incorrect? How would you change it?

    Is it because those aren't found in the SI units? I'm not sure how to change it.

    3. What's the percent uncertainty for a measurement of 9.73?

    I do not know how to do this.
  2. jcsd
  3. Sep 11, 2007 #2


    User Avatar
    Homework Helper

    1)I think the first question is talking about the inaccessibility of the precise definition of certain quantities... like the meter is defined as "the distance travelled by light in absolute vacuum in 1/299,792,458 of a second."

    That's very precise... but how practical is it... It's useful for standards to be invariable...

    2) I'm guessing it's significant figures that's the problem here.

    3) I think the uncertainty is 1 in the last digit divided by the number * 100%... for example the uncertainty of 5.63 = (0.01/5.63)*100% = 0.178%
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook