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: **
30, 22
8
The numbers above are both in units of centimeters. In order to get the length of my rubber band I placed the top of the rubber band at the 30cm mark on my ruler and observed the reading at which the bottom of the rubber landed and this was the 22cm mark so the length of my rubber band is 8cm. I placed a series of one to six marks on my rubber bands and they are hung on the chain in a ascending order. This rubber band is number 1 and I think that the measurement is within .01cm of the actual measurement.
** The basis for your uncertainty estimate: **
because when i look at my ruler i can tell the lenth of the rubber band down to the millimeter and I can add one digit for the uncertainty allowed by sig figs.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
30, 22
5, 12.60
0, 7.35
2, 9.50
0, 7.25
1, 8.65
END
8.00, 7.60, 7.35, 7.50, 7.25, 7.65
1,2,3,4,5,6,
The uncertainty is .01
** Distances between ends when supporting 2 dominoes **
8.00, 7.80, 7.45, 7.15, 7.50, 7.80
These measurements are recorded in cm are the result of the weight of two dominos.
** Lengths when supporting 4, 6, ... dominoes: **
8.50, 8.00, 7.50, 8.00, 8.25, 7.80
The numbers recorded are for four dominos
8.70, 8.20, 7.80, 8.00, 7.80, 8.00
The numbers above are listed for 6 dominos
9.00, 8.50, 8.20, 8.45, 8.0, 8.50
The numbers above are listed for 8 dominos
9.00, 8.80, 8.40, 8.50, 9.05, 9.45
The numbers above are listed for 10 dominos
END
** Your table of force in Newtons vs. length in cm for all rubber bands **
8.00, 7.60, 7.35, 7.50, 7.25, 7.65, .19 Newtons
8.00, 7.80, 7.45, 7.15, 7.50, 7.80, .38 Newtons
8.50, 8.00, 7.50, 8.00, 8.25, 7.80, .76 Newtons
8.70, 8.20, 7.80, 8.00, 7.80, 8.00, 1.14 Newtons
9.00, 8.50, 8.20, 8.45, 8.00, 8.50, 1.52 Newtons
9.00, 8.80, 8.40, 8.50, 9.05, 9.45, 1.90 Newtons
** Describe the graph of your first rubber band **
Line 1: Decreasing then increasing then once again decreasing
Line 2: Decreasing at a constant rate then increasing at a constant rate
Line 3: Decreasing at a constant rate then increasing at a constant rate then decreasing again
Line 4: Decreasing then increasing then decreasing then increasing then decreasing.
Line 5 Decreasing then increasing then decreasing then increasing
Line 6 Decreasing at a constant rate then increasing at a constant rate
END
** The tension force in your first rubber band at length 9.8 cm: **
2.0 newtons
** The length of your first rubber band when tension is 1.4 N: **
8.5cm
** 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: **
.10, .10, .40, .50, 1.0, 1.0,
.09, .28, .36, .64, .52, .90
** 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: **
8.00, 8.00, 8.50, 8.70, 9.00, 9.00
this is the numbers that i observed I could not understand which graph you were refering to that had the corresponding forces, here is the numbers that i observed.
You were to graph the force versus length. This means that the force goes on the 'vertical' axis and the length on the 'horizontal' axis. The curve the best this the data points will probably not go through any of the actual data points. The purpose here is to compare the accuracy of the curve, which should tend to 'smooth out' uncertainties in measurement, to that of your direct measurements.
** The typical error you estimate when predicting force for a given length from your graphs: **
The values in my table that I reported because I observed them with my own tools, I would say that the uncertainty in the force would be +-,12 and the reason I say this is because the graph does not remain constant.
Your observations are good only to within +-.1 cm; the smoothed curve you get from a number of data points could well be more accurate.
** The typical error you estimate when predicting length for a given force from your graphs: **
+-.13 cm because the numbers vary to much to be within .05 cm.
** **
3 hours
** **
You appear to have very good data. See my notes about the graph and let me know if you have questions.