rubber band calibration

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, 21.4

11.4

I subtracted my ending measurement from my first, this is the length of the rubber band. The rubber band is marked by a single dot using a permanent marker and is accurate within .02cm.

** #$&* The basis for your uncertainty estimate: **

I used .02cm because I figured I was within .01 at the beginning and the end of my measurement.

** #$&* Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **

10, 21.4

10, 21.2

10, 21.1

10, 21.3

10, 21.1

10, 21.2

End

11.4, 11.2, 11.1, 11.3, 11.1, 11.2

Each band has dots written by a permanent marker indicating which band it is.

+- .02cm

** #$&* Distances between ends when supporting 2 dominoes **

11.6, 11.5, 11.5, 11.6, 11.3, 11.6

Results from 2 dominoes

** #$&* Lengths when supporting 4, 6, ... dominoes: **

11.8, 11.7, 11.6, 11.8, 11.6, 11.7

12.1, 11.9, 11.9, 12.1, 11.9, 12

12.5, 12.1, 12.2, 12.5, 12.1, 12.2

12.6, 12.3, 12.4, 12.5, 12.2, 12.3

End

** #$&* Your table of force in Newtons vs. length in cm for all rubber bands **

11.4, 11.2, 11.1, 11.3, 11.1, 11.2, .19

11.6, 11.5, 11.5, 11.6, 11.3, 11.6, .38

11.8, 11.7, 11.6, 11.8, 11.6, 11.7, .76

12.1, 11.9, 11.9, 12.1, 11.9, 12, 1.14

12.5, 12.1, 12.2, 12.5, 12.1, 12.2, 1.52

12.6, 12.3, 12.4, 12.5, 12.2, 12.3, 1.71

End

My table consisted of 8 columns 4 of which contained measurements for the four rubber bands in centimeters using the single reduced ruler that was included in our kit, the other columns contained the amount of force exerted by Earth this was measured in Newtons.

** #$&* Describe the graph of your first rubber band **

1, Increasing at an increasing rate throughout.

2, Increasing at an increasing rate then increasing at a decreasing rate

3, Increasing at an increasing rate then increasing at a decreasing rate

4, Increasing at an increasing rate then increasing at a decreasing rate

5, Increasing at an increasing rate throughout.

6, Increasing at an increasing rate then increasing at a decreasing rate

** #$&* The tension force in your first rubber band at length 9.8 cm: **

0 Newtons

** #$&* The length of your first rubber band when tension is 1.4 N: **

12.3 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: **

.19, .4, .7, 1, 1.61, 1.71

I have a few points that stray from my curve, but for the most part most of them fit very well.

** #$&* 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: **

11.4, 11.55, 11.8, 11.85, 12.1, 12.45

0, -0.5, 0, -.25, -.4, -.15

** #$&* The typical error you estimate when predicting force for a given length from your graphs: **

Both of mine are so close that there isn’t much difference. If there was a difference I would chose the curve because it gives you the best fit line between points and should be a good average of what the points should be.

+-0.05N

My graph is broken down into every .2 Newtons, so I figured that I could pinpoint a force to .1 +-0.05

** #$&* The typical error you estimate when predicting length for a given force from your graphs: **