PHY 201
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): **
** #$&* first line ruler markings, distance in actual cm between ends, how obtained: **
3 cm, 10.05 cm
7.05 cm
The value in the second line was calculated by finding the difference between the numbers in the first line. This value is the length of the rubber band. The rubber band is marked with the number 1. The accuracy of this measurement is approximately +- .05 cm.
** #$&* The basis for your uncertainty estimate: **
The basis for the uncertainty is eyeballing the measurement and making sure that the ruler and rubber band stay steady.
** #$&* Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
3.00 cm, 10.05 cm
5.00 cm, 12.89 cm
2.00 cm, 9.33 cm
5.00 cm, 12.40 cm
5.00 cm, 12.48 cm
5.00 cm, 12.40 cm
End
7.05 cm, 7.89 cm, 7.33 cm, 7.40 cm, 7.48 cm, 7.40 cm
1, 2, 3, 4, 5, 6
+- .05
** #$&* Distances between ends when supporting 2 dominoes **
7.20 cm, 8.11 cm, 7.57 cm, 7.58 cm, 7.60 cm, 7.50 cm
Weight of two dominoes
** #$&* Lengths when supporting 4, 6, ... dominoes: **
7.57 cm, 8.48 cm, 7.84 cm, 7.78 cm,7.67 cm, 7.63 cm
4
7.60 cm, 8.54 cm, 8.05 cm, 8.00 cm, 7.84 cm, 7.95 cm
6
7.85 cm, 8.70 cm, 8.21 cm, 8.17 cm, 8.24 cm, 8.10 cm
8
8.00 cm, 8.97 cm, 8.47 cm, 8.45 cm, 8.53 cm, 8.35 cm
10
End
** #$&* Your table of force in Newtons vs. length in cm for all rubber bands **
7.05, 7.89, 7.33, 7.40, .19
7.20, 8.11, 7.57, 7.58, .38
7.57, 8.48, 7.84, 7.78, .76
7.60, 8.54, 8.05, 8.00, 1.14
7.85, 8.70, 8.21, 8.17, 1.52
8.00, 8.97, 8.47, 8.45, 1.90
End
Column 1 is the length of rubber band 1 measured in cm.
Column 2 is the length of rubber band 2 measured in cm.
Column 3 is the length of rubber band 3 measured in cm.
Column 4 is the length of rubber band 4 measured in cm.
Column 5 is the force exerted in Newtons for the number of dominoes.
** #$&* Describe the graph of your first rubber band **
The first rubber band graph is increasing at a constant rate, then increasing at an increasing rate.
The second rubber band graph is increasing at a constant rate, then increasing at an increasing rate.
The third rubber band graph is increasing at an increasing rate throughout.
The fourth rubber band graph is increasing at an increasing rate throughout.
End
Just did the graphs for the first four rubber bands, because that is what you stated previously.
** #$&* The tension force in your first rubber band at length 9.8 cm: **
3.3
** #$&* The length of your first rubber band when tension is 1.4 N: **
7.85
** #$&* 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: **
.23, .30, .68, 1.07, 1.45, 1.82
.04, .08, .08, .07, .07, .18
** #$&* The lengths predicted for forces .19 N, .38 N, .76 N, 1.14 N, etc. by the curve for your first rubber band; the deviations of your actual observations from these predictions: **
7.03, 7.28, 7.61, 7.65, 7.90, 8.08
.05, .08, .04, .05, .05, .08
** #$&* The typical error you estimate when predicting force for a given length from your graphs: **
I would have more faith in the curve, because it will give a more consistent value even if one of my measurements is a little off.
I would give the graph an uncertainty of +- .05 because that seems to be about the average that the measurements on the graph are off.
** #$&* The typical error you estimate when predicting length for a given force from your graphs: **
I would give an uncertainty of approximately +- .10, because during the actual measurements I gave an uncertainty of +- .05. The graph measurements seem to be off by about the same amount.
** **
2.5 hours
** **
&#Very good responses. Let me know if you have questions. &#