Uncertainties of a group of results

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
1 reply · 1K views
Tangeton
Messages
62
Reaction score
0
I got a table for a simple pendulum. I have 8 lengths, from 0.20m going up by 0.01 to 0.27. For each length, I have time for 10 oscillations (10T) that I've measured, and I have repeated the measurement twice for each length. Then I got the average time for 10T. I divided this average to give me an average for time period of one oscillation, T. I've plotted a graph of T2 against L, and so I also worked out T2 for each lengths' period time, T.

I am stuck on the uncertainty. I have tired tried to work it out but when I do it for T I get 6.77%, and I do it for the spread of my results for T, but when I rise it to the power of 2 to get T2 its 45.89%. I can't have such a huge uncertainty. And also I am worried because it is uncertainty in measurement but I can firmly say that I didn't measure T but 10T, and so should I do the uncertainty for average 10T instead?

What uncertainty would be the best to put down on my write up?

I'm an A Level physics student.

Thank you for all your help!
 
Physics news on Phys.org
No way one can untangle this. 46 is the square of 6.8, but that's not the way errors propagate!
Show your work.