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: **
24.25, 40.00
6.35
The rubber band measured 15.75 cm on the doubly reduced ruler. In a previous assignment I found that 2.48 cm on the doubly reduced ruler is equivalent to 1 actual cm. Therefore, I took 15.75 cm and multiplied it by (1 cm / 2.48 cm) to get the actual number of centimeters the top rubber band measured when one domino was placed in the bag (6.35 cm). The uncertainty in this measurement is +-.02 cm. This rubber band is marked with roman numeral i.
** The basis for your uncertainty estimate: **
The uncertainty of +-.02 cm is based on gathering measurements on the doubly reduced ruler to the nearest .5 mm or .05 cm. When this measurement is multiplied by 1 actual cm / 2.48 cm on doubly reduced ruler we get the uncertainty of +-.02 cm.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
24.25 , 40.00
24.95 , 40.00
24.90 , 40.00
24.85 , 40.00
24.80 , 40.00
24.80 , 40.00
End
6.35 , 6.07 , 6.09 , 6.11 , 6.13, 6.13
The above measurements were taken on the doubly reduced ruler and include measurements for rubber bands i, ii, iii, iv, v, and vi, respectively.
The above actual measurements include an uncertainty of +-.02 cm.
** Distances between ends when supporting 2 dominoes **
6.55 , 6.30 , 6.52 , 6.37 , 6.39 , 6.33
The above are the measurements of rubber bands i - vi, respectively, with 2 dominoes in the bag.
** Lengths when supporting 4, 6, ... dominoes: **
7.10 , 6.72 , 6.92 , 6.83 , 6.85 , 6.88
4
7.70 , 7.20 , 7.34 , 7.43 , 7.58 , 7.46
6
8.51 , 7.77 , 7.90 , 8.25 , 8.59 , 8.27
8
End
** Your table of force in Newtons vs. length in cm for all rubber bands **
6.35 , 6.07 , 6.09 , 6.11 , 6.13 , 6.13 , .19
6.55 , 6.30 , 6.52 , 6.37 , 6.39 , 6.33 , .38
7.10 , 6.72 , 6.92 , 6.83 , 6.85 , 6.88 , .76
7.70 , 7.20 , 7.34 , 7.43 , 7.58 , 7.46 , 1.14
8.51 , 7.77 , 7.90 , 8.25 , 8.59 , 8.27 , 1.52
End
** Describe the graph of your first rubber band **
Increasing at a decreasing rate then increasing at a slightly lower decreasing rate
Very briefly increasing at an increasing rate then increasing at a slightly decreasing rate
Increasing at an increasing rate then increasing at a decreasing rate
Increasing at an increasing rate then increasing at a decreasing rate
Increasing at a slightly increasing rate then increasing at a decreasing rate
Increasing at a decreasing rate throughout
** The tension force in your first rubber band at length 9.8 cm: **
1.8 N
** The length of your first rubber band when tension is 1.4 N: **
8.25 cm
** 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: **
.20 , .40 , .79 , 1.14 , 1.5
The estimates differ from the actual by 0-5%.
** 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: **
6.30 , 6.50 , 7.00 , 7.70 , 8.55
0.05 , 0.05 , 0.10 , 0.00 , 0.04
** The typical error you estimate when predicting force for a given length from your graphs: **
I have more faith in the curve because of the uncertainties in observation.
The uncertainty when estimating a force for a given length would be about +-.1 N because the uncertainty in the lengths is +-.02 and the graph between +-.02 changes by about .1 N.
** The typical error you estimate when predicting length for a given force from your graphs: **
The uncertainty for the length given a force would be about +-.05 because there is already +-.02 uncertainty in length plus the uncertainty in the curve of the graph.
** **
3.5 hours
** **
&#Your work looks very good. Let me know if you have any questions. &#