• Support PF! Buy your school textbooks, materials and every day products Here!

Propogation of uncertainty in a data set (finger-math at most)

  • #1

Homework Statement


I have conducted a simple lab, that involves getting the distance traveled by a vertically falling weight at certain time intervals. Velocity is calculated for every time interval (distance traveled per time interval). Then I graph velocity versus time to get acceleration which comes out decently close to g.

Now the part I am confused about is calculating uncertainty for:
a) Velocity
b) Acceleration
c) y-intercept of velocity vs. time graph (acceleration line)

Absolute uncertainty for time is +-0.010s, and +-0.001m (1mm) for distance.

Homework Equations


Relative uncertainty % = Absolute Uncertainty / Measured value
* and / of uncertainties with each other adds their relative uncertainties

The Attempt at a Solution


Since this is of a data set, you have many measured values, and it makes no sense to have a single relative uncertainty in the above equation. It would be different for each data point, correct?

Am I missing something from this concept? Or do I literally have to calculate out a different uncertainty for each velocity? Another possibility could be finding relative uncertainty for the first data point and using that % throughout the problem for all of them but that cant be right...
 

Answers and Replies

  • #2
mump
 

Related Threads on Propogation of uncertainty in a data set (finger-math at most)

  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
4K
Replies
5
Views
143
Replies
1
Views
1K
Replies
6
Views
2K
Replies
0
Views
1K
  • Last Post
Replies
0
Views
1K
Replies
3
Views
599
  • Last Post
Replies
5
Views
620
Top