# Relative Uncertanity

1. Sep 18, 2010

### gcsm

Absolute Uncertanity

1. The problem statement, all variables and given/known data
A distance R is measured to be 4.000±0.002 m
What is the absolute uncertainty in R to the power of negative two?

2. Relevant equations

3. The attempt at a solution

4^-2 = 0.00625
0.002^-2 = 250000

Im stuck at this question I have no idea where to go, any help would be appreciated!

Last edited: Sep 18, 2010
2. Sep 18, 2010

### Thaakisfox

umm you already gave the absolute uncertainty, it is 0,002m...

3. Sep 18, 2010

### gcsm

but I tried that, meaning 0.002 and thats not it, I also tried 250000 (using SI) and that isnt correct either...not really sure where to go...

4. Sep 18, 2010

### Thaakisfox

Are you looking for the absolute or relative uncertainty? as in the thread title you say relative, but then in the problem description you say absolute.

The absolute is 0.002m that is 100%, then most probably you are looking for the relative uncertainty.
That is divide the absolute by the average.

5. Sep 18, 2010

### gcsm

sorry for the confusion, the question is as follows:
What is the absolute uncertainty in R to the power of negative two?

but wouldnt you have to do something to the +-0.002m?