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: **
8.5cm, 15.8cm
7.3cm
I subtracted the position of the start of the rubber band from the position of the end of the rubber band to find the total length of the rubber band. I am using an actual ruler and it seems likely to be accurate within +/- .1cm.
** The basis for your uncertainty estimate: **
The ruler is marked off in cm, and the system is moving very slightly when I make my measurments.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
8.5cm, 15.8cm
23.3cm, 30.8cm
39.6cm, 46.9cm
55.2cm, 62.5cm
70.6cm, 78.0cm
85.3cm, 92.9cm
END
7.3cm, 7.5cm, 7.3cm, 7.3cm, 7.4cm, 7.6cm
Again, within +/-.1cm I'm pretty sure.
** Distances between ends when supporting 2 dominoes **
7.6cm, 7.6cm, 7.4cm, 7.4cm, 7.4cm, 7.6cm
Two Dominoes
** Lengths when supporting 4, 6, ... dominoes: **
8cm, 7.9cm, 7.6cm, 7.6cm, 7.6cm, 7.9vm
4
8cm, 8.1cm, 7.9cm, 7.9cm, 8cm, 8cm
6
8.2cm, 8.4cm, 8.1cm, 8.1cm, 8.2cm, 8.4cm
8
8.7cm, 8.7cm, 8.4cm, 8.3cm, 8.4cm, 8.6cm
10
END
** Your table of force in Newtons vs. length in cm for all rubber bands **
7.3cm, 7.5cm, 7.3cm, 7.3cm, 7.4cm, 7.6cm, .19N
7.6cm, 7.6cm, 7.4cm, 7.4cm, 7.4cm, 7.6cm, .38N
8cm, 7.9cm, 7.6cm, 7.6cm, 7.6cm, 7.9cm, .76N
8cm, 8.1cm, 7.9cm, 7.9cm, 8cm, 8cm, 1.14N
8.2cm, 8.4cm, 8.1cm, 8.1cm, 8.2cm, 8.4cm, 1.52N
8.7cm, 8.7cm, 8.4cm, 8.3cm, 8.4cm, 8.6cm, 1.90N
END
Each collumn represents the length of the respective rubber band in my chain under different newtons of stress.
** Describe the graph of your first rubber band **
Increasing at an increasing rate
Very constant slope thus a constant rate of increase
Increasing at a decreasing rate
Increasing at an increasing rate
Very constant slope thus a constant rate of increase
Increasing at an increasing rate
** The tension force in your first rubber band at length 9.8 cm: **
2.5N
** The length of your first rubber band when tension is 1.4 N: **
8.3cm
** 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, .45N, 1N, 1N, 1.35N, 2N
-.2N, +.7N, +.24N, -.14N, -.17N, +.1N
** 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: **
7.35cm, 7.55cm, 7.85cm, 7.85cm, 8.25cm, 8.4cm
+.05cm, -.05cm, -.15cm, -.15cm, +.05cm, -.3cm
** The typical error you estimate when predicting force for a given length from your graphs: **
Probably the curve since it seems to take an average of the results and has less consideration in extreme data points. I would guess the uncertianty to be within +/-.25N since that is the average of the differences I saw in the above force question.
** The typical error you estimate when predicting length for a given force from your graphs: **
Roughly +/-.1cm since this is the average of the sum of the length discrepecies in the above length question.
** **
Probably 3 hours total.
** **
&#Very good work. Let me know if you have questions. &#