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: **
10.0, 17.3
7.30
The number in the second line is the actual length of the rubber band. I subtracted the first measurement (from the top end) from the second measurement (from the bottom end) to end up with the difference which is the actual length of the rubber band. The measurement is accurate within about +/- .1 cm.
** The basis for your uncertainty estimate: **
I used a standard ruler for this experiment and it is marked off in cm with the smallest readable interval being 1 mm which is the same as .1 cm. That is why I estimated that it should be accurate within +/- .1cm.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
10, 17.3
10, 17.3
10, 17.6
10, 17.6
10, 17.3
10, 17.3
End
7.3, 7.3, 7.6, 7.6, 7.3, 7.3
The markings on the rubber bands were 1, 2, 3, 4 , 5, and 6.
I used a standard ruler for this experiment and it is marked off in cm with the smallest readable interval being 1 mm which is the same as .1 cm. That is why I estimated that it should be accurate within +/- .1cm.
** Distances between ends when supporting 2 dominoes **
7.5, 7.5, 7.8, 7.8, 7.5, 7.5
Obtained from the weight of 2 dominoes.
** Lengths when supporting 4, 6, ... dominoes: **
7.7, 7.5, 7.6, 7.9, 7.6, 7.9
4
7.9, 7.7, 8.2, 8.3, 7.5, 8.0
6
8.3, 7.9, 8.5, 8.1, 8.1, 8.6
8
End
** Your table of force in Newtons vs. length in cm for all rubber bands **
7.3, 7.3, 7.6, 7.6, .19N
7.5, 7.5, 7.8, 7.8, .38N
7.7, 7.5, 7.6, 7.9, .76N
7.9, 7.7, 8.2, 8.3, 1.14N
8.3, 7.9, 8.5, 8.1, 1.52N
The data above represents the measurements of the length of the first 4 bands at each different force. The last number in each row is represents the force. The length is measured in centimeters and the force is measured in Newtons.
** Describe the graph of your first rubber band **
1.Increasing at an a constant rate then at an increasing rate then back at a constant rate.
2. Increasing at an increasing rate then increasing at a decreasing rate then increasing at an increasing rate.
3. Increasing at a constant rate then decreasing and then increasing at an increasing rate.
4.Increasing at an increasing rate then decreasing at a decreasing rate.
5.Increasing at an increasing rate then decreasing at a decreasing rate then increasing.
6. Increasing at an increasing rate then at a decreasing rate then at an increasing rate.
END
** The tension force in your first rubber band at length 9.8 cm: **
2.28
** The length of your first rubber band when tension is 1.4 N: **
8.2
** 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: **
.17, .48, .85, 1.11, 1.37
The curve differs on average approximately .104 N from the actual observed force.
** 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: **
7.3, 7.45, 7.75, 8.0
The curve differs on average approximately .05 cm from the actual observed length.
** The typical error you estimate when predicting force for a given length from your graphs: **
The estimated curve because the observed values are more likely to suffer from human/optical erros. I would estimate approximately +/- .104 N.
This is because this is the average force difference in N as calculated from the 1st graph.
** The typical error you estimate when predicting length for a given force from your graphs: **
The length should be within +/- .05 cm of the observed length because this is the average difference in the lengths as observed from the 1st graph.
** **
3 hours
** **
Good work on this experiment.