## Uncertainties

### Vixus

Posted 13 May 2006 - 03:42 PM

How are the various uncertainties calculated?
I know how to calculate range/n, I think that's random error.

But what about percentage and absolute error? Maybe it would be easier if someone solved Q1 from 2003.

### broughy

Posted 14 May 2006 - 12:03 AM

er, you'd need to show me that question.....i'd have a go at it, not making any promises though! don't remember much about errors from the days of school!

### Vixus

Posted 14 May 2006 - 11:33 AM

Acceleration of a car is measured. Following data gathered:

s = 3.54 +- 0.01m
t = 2.53, 2.29, 2.34, 2.36, 2.65, 2.53 s

a = 2s/t2

Calculate random uncertainty in time measurement.
Calculate % uncertainty in average acceleration.
Express numerical result in form

final value +- absolute uncertainty

### Pringles

Posted 14 May 2006 - 03:18 PM

Here is how I done this.

Average time firstly is = 2.45 seconds

Average acceleration =

Random uncertainty =

Percentage uncertainty in distance =
= +/- 0.28%

Since this value is less than a third of the percentage uncertainty in time then it can be ignored.

Therefore uncertainty in = +/- 4.9%

so in numerical form = 1.18 +/- 0.06m/s/s

### broughy

Posted 14 May 2006 - 06:08 PM

i'd say, on first glance, that that looks right to be

### skint_student

Posted 14 May 2006 - 09:14 PM