PHY 121
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: **
10, 17.4
7.4
I obtained this measurement by taking a centimeter ruler and using the 10 cm mark at the top of the rubber band and then measured it to its end. I believe that my measure is accurate +- .02.
** The basis for your uncertainty estimate: **
When I first measured the rubber band it was longer then when I measured it with the 10 cm mark as the start.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
10.0, 17.4
22.9, 29.8
35, 42.2
47.4, 54.6
60, 67.5
72.7, 80.3
End
7.4, 6.9, 7.2, 7.2, 7.5, 7.6
1, 2, 3, 4, 5, 6
+- .02
** Distances between ends when supporting 2 dominoes **
7.8, 7.5, 7.5, 7.5, 7.5, 7.7
These results are from the weight of two dominoes in the bag at the end of the chain.
** Lengths when supporting 4, 6, ... dominoes: **
7.7, 7.8, 7.8, 7.8, 7.9, 7.8
4
8, 8, 7.7, 7.7, 7.8, 8
6
8, 8.1, 8, 8, 8.1, 8.1
8
8.2, 8.2, 8.1, 8.1, 8.2, 8.5
10
I ran out of dominos, none of my rubber bands exceeded the 30% of there initial length.
** Your table of force in Newtons vs. length in cm for all rubber bands **
Band #1
7.4, .19
7.6, .38
7.7, .79
8, 1.14
8, 1.52
8.2, 1.9
End
Band #2
6.9, .19
7.5, .38
7.8, .76
8, 1.14
8.1, 1.52
8.2, 1.9
End
Band #3
7.2, .19
7.5, .38
7.8, .76
7.7, 1.14
8, 1.52
8.1, 1.9
End
Band #4
7.2, .19
7.5, .38
7.8, .76
7.7, 1.14
8, 1.52
8.1, 1.9
End
The first numbers and the lengths of each rubber band in cm. The second number is the pull of the domino in newtons.
** Describe the graph of your first rubber band **
The lines for the first 4 rubber bands curve in a way that looks like an exponential curve.
The lines for the 5th and 6th rubber bands almost look linear.
End
** The tension force in your first rubber band at length 9.8 cm: **
I would estimate a force of 2.6 newtons
** The length of your first rubber band when tension is 1.4 N: **
8 cm in length would be my estimate for a force of 1.4 using the graph for the 1st rubber band.
** 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: **
3, 3.4, 4.4, 4.8, 5.2
2.81, 3.02, 3.64, 3.66, 3.68
** 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: **
7.45, 7.55, 7.8, 7.98, 8.5, 8.2
.05, .25, .1, .02, .5, 0
** The typical error you estimate when predicting force for a given length from your graphs: **
The values that I measured.
+-.02
** The typical error you estimate when predicting length for a given force from your graphs: **
+-.02
** **
1 hour
** **
&#Your work looks very good. Let me know if you have any questions. &#