Phy231
Your 'rubber band calibration' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** #$&* Your initial comment (if any): **
3/10/10 2pm
** #$&* first line ruler markings, distance in actual cm between ends, how obtained: **
10.00cm, 17.25cm
7.25cm
I held the ruler up to the first rubber band. The number in the second line is the length of the first rubber band with one domino in the bag. This rubber band is marked #1. The measurement is accurate within +-.05cm.
** #$&* The basis for your uncertainty estimate: **
I looked at the end marking several times. It is somewhere between 17.0cm and 17.5cm. So my certainty is that the measurement is accurate within +-.05cm.
** #$&* Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
10.00cm, 17.25cm
4.00cm, 11.25cm
5.00cm, 12.10cm
7.00cm, 14.00cm
10.00cm, 16.75cm
20.00cm, 27.20cm
END
7.25cm, 7.25cm, 7.10cm, 7.00cm, 6.75cm, 7.20cm
1, 2, 3, 4, 5, 6
+-.05cm
** #$&* Distances between ends when supporting 2 dominoes **
7.30cm, 7.30cm, 7.25cm, 7.10cm, 7.25cm, 7.40cm
These lengths are with two rubber bands in the bag.
** #$&* Lengths when supporting 4, 6, ... dominoes: **
7.50cm, 7.60cm, 7.40cm, 7.50cm, 7.75cm, 7.60cm
4
7.75cm, 7.90cm, 7.65cm, 7.75cm, 7.85cm, 7.80cm
6
7.85cm, 8.10cm, 7.95cm, 8.03cm, 8.25cm, 7.95cm
8
8.13cm, 8.45cm, 8.20cm, 8.30cm, 8.45cm, 8.15cm
10
END
** #$&* Your table of force in Newtons vs. length in cm for all rubber bands **
7.25cm, 7.25cm, 7.10cm, 7.00cm, 6.75cm, 7.20cm, .19N
7.30cm, 7.30cm, 7.25cm, 7.10cm, 7.25cm, 7.40cm, .38N
7.50cm, 7.60cm, 7.40cm, 7.50cm, 7.75cm, 7.60cm, .76N
7.75cm, 7.90cm, 7.65cm, 7.75cm, 7.85cm, 7.80cm, 1.14N
7.85cm, 8.10cm, 7.95cm, 8.03cm, 8.25cm, 7.95cm, 1.52N
8.13cm, 8.45cm, 8.20cm, 8.30cm, 8.45cm, 8.15cm, 1.9N
END
The first column is the length of the rubber bands with an exertion force of .19N. The second column is the length of the rubber bands with an exertion of .38N. This continues with each column, the first 6 numbers are of lengths of the rubber bands and the seventh number is the exertion in Newtons on the rubber bands.
** #$&* Describe the graph of your first rubber band **
Increasing at an decreasing rate throughout
All six rubber bands are oblong and approximately .25cm wide and between 8.13cm and 8.45cm long
END
** #$&* The tension force in your first rubber band at length 9.8 cm: **
3.2N
** #$&* The length of your first rubber band when tension is 1.4 N: **
7.92cm
** #$&* The forces at your observed lengths the 1st rubber band, as given by the curve, and the deviations of those curve-predicted lengths from the observed lengths: **
.17N, .4N, .79N, 1.275N, 1.33N, 1.65N
.02N, .02N, .03N, .13N, .19N, .25N
** #$&* The lengths predicted for forces .19 N, .38 N, .76 N, 1.14 N, etc. by the curve for your first rubber band; the deviations of your actual observations from these predictions: **
7.30cm, 7.41cm, 7.52cm, 7.70cm, 7.93cm, 8.21cm
.05cm, .11cm, .02cm, .05cm, .08cm, .08cm
** #$&* The typical error you estimate when predicting force for a given length from your graphs: **
I have more faith in my measurements because I actually measured them. I saw with my own eyes. Also the curve was made with my measurements and the curve was also made by me trying to best fit the information.
Based on the previous estimates I would say +-.3N.
** #$&* The typical error you estimate when predicting length for a given force from your graphs: **
Based on the previous estimates I would say +-.15cm and that's a generous estimate.
** **
2hrs 15min
** **
3/10/10 4:30pm
&#This looks good. Let me know if you have any questions. &#