- #1

_Mayday_

- 808

- 0

**[SOLVED] Percentage uncertainty**

If I measure the time of something to one decimal place, let's say I get 0.6 seconds. Would my absolute uncertainty for this be 0.05 seconds? I have read that it should be 0.01 seconds but that does not make sense to me. Surely my figures form that result could range from 0.55 to 0.65 so that is 0.05 seconds either way?

My actual question here is measuring the percentage uncertainty. If I measure a distance of 0.150 metres, with an absolute uncertaintly of 0.001 metres and a time of 0.6 with an absolut euncertainty of 0.05, what would be the percentage uncertaintly of the result of the average speed.

I am measuring time to a tenth of a second, and distance to the nearest millimetre.Here is my attempt.

[tex]speed=\frac{distance}{time}[/tex]

% uncertainty for the time is [tex]\frac{0.05}{0.6}[/tex]

% uncertainty for the distance is [tex]\frac{0.001}{0.150}[/tex]

Then to calculate the percentage uncertainty of the speed calculated I would plug those figures into the formula?Any help would be great!

Last edited: