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: **
1, 6.8
5.8 cm
I numbered them 1-6 using a Sharpie marker and put them in order 1-6 going down with the baggie connected to 6. I believe that I'm accurate within .05 cm.
** The basis for your uncertainty estimate: **
I'm using the paper rulers and the uncertainty seemed to be close to .05 for the double one that I'm using so that is why I stated this.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
1, 6.8
1, 6.6
1, 6.45
1, 6.6
1, 6.4
1, 6.3
End
5.8, 5.6, 5.45, 5.6, 5.4, 5.3
1, 2, 3, 4, 5, 6
.05 is the uncertainty
** Distances between ends when supporting 2 dominoes **
5.8, 5.6, 5.7, 5.7, 5.6, 5.6
Two dominoes
** Lengths when supporting 4, 6, ... dominoes: **
6.1, 5.7, 5.7, 5.8, 5.7, 5.7
4
6.3, 5.9, 5.9, 6.1, 5.9, 5.8
6
6.45, 6.1, 6.15, 6.3, 6.1, 6.0
8
End
** Your table of force in Newtons vs. length in cm for all rubber bands **
5.8, 5.6, 5.45, 5.6, 5.4, 5.3 - 1 domino(.19 Newtons)
5.8, 5.6, 5.7, 5.7, 5.6, 5.6 - 2 dominoes (.38 Newtons)
6.1, 5.7, 5.7, 5.8, 5.7, 5.7 - 4 dominoes (.76 Newtons)
6.3, 5.9, 5.9, 6.1, 5.9, 5.8 - 6 dominoes(1.14 Newtons)
6.45, 6.1, 6.15, 6.3, 6.1, 6.0 - 8 dominoes (1.52 Newtons)
End
Measurements of rubberbands 1-6 are in order with how many dominoes are pulling down with the amount of force.
** Describe the graph of your first rubber band **
I think increasing at an increasing rate would describe most of these graphs best. They start out slow and then the incline becomes great as plots are made after the first couple. All graphs slope upwards.
End
** The tension force in your first rubber band at length 9.8 cm: **
3.5 Newtons
** The length of your first rubber band when tension is 1.4 N: **
6.4 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: **
.35, .35, 1.3, 1.4, 1.45
.16, .03, .54, .26, .07
** 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: **
4.5 cm, 5 cm., 5.5 cm., 6 cm, 6.5 cm
1.3 cm, .8 cm, .6 cm, .3 cm, .05 cm
** The typical error you estimate when predicting force for a given length from your graphs: **
I don't have any faith in the curve that I draw. I can't do a good job with this for some reason. Plus I don't do exact plots; I try to eyeball them instead of doing precise small markings.
Using the above question, I analyzed how off I was by my curve(taking an average of those numbers), and it seems that I might be off by about .2 N.
** The typical error you estimate when predicting length for a given force from your graphs: **
Looking at the numbers above, it appears that I may be off by .6 cm.
** **
2 hours
** **
2/11 at 12:19 I'm hoping that by completing this form online instead of copying it into notepad, my answers will be easier to follow.
You can use whichever format you prefer. Some experiments might do better with the form, others with the copy. If your ISP is reliable, then the chance of losing data if the form crashes is small; however I do recommend that you keep a backup. Don't trust original data to the form.