phy201
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.
** #$&* Your initial comment (if any): **
I am going back through and resubmitting labss that needed revision..here is the second revision the the rubber band calibration experiment....I think I have it this time. :)
Thanks
natalie
** #$&* first line ruler markings, distance in actual cm between ends, how obtained: **
** #$&* The basis for your uncertainty estimate: **
** #$&* Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
** #$&* Distances between ends when supporting 2 dominoes **
** #$&* Lengths when supporting 4, 6, ... dominoes: **
** #$&* Your table of force in Newtons vs. length in cm for all rubber bands **
** #$&* Describe the graph of your first rubber band **
** #$&* The tension force in your first rubber band at length 9.8 cm: **
** #$&* The length of your first rubber band when tension is 1.4 N: **
** #$&* The forces at your observed lengths the 1st rubber band, as given by the curve, and the deviations of those curve-predicted lengths from the observed lengths: **
** #$&* 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: **
** #$&* The typical error you estimate when predicting force for a given length from your graphs: **
** #$&* The typical error you estimate when predicting length for a given force from your graphs: **
** **
** **
rubber band calibration
phy201
Revision to lab rubber band calibration
rubber band calibration
phy201
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): **
** #$&* first line ruler markings, distance in actual cm between ends, how obtained: **
1cm, 5.0cm
3.3 cm
I obtained these number using one of the paper rulers, the first is the measurement of the first rubber band marked 1 from one end to the other end, the second number is the distance from the end of the first rubber band to the beginning of the second rubber band. I beleive the uncertainty to be within of .1 of a cm.
** #$&* The basis for your uncertainty estimate: **
Because of the marking on the ruler, I can see the point were the rubber band ends.
** #$&* Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
1cm, 5.0cm
1cm, 5.1cm
1cm, 5.0cm
1cm, 4.9cm
1cm, 5.1cm
1cm, 4.9cm
End
3.3cm, 3.8cm, 3.2cm, 3.1cm, 3.2cm
1-2, 2-4, 4-5, 5-6
uncertainty of .1 cm
If the ends of the first rubber band are at 1.0 cm and 5.0 cm, then its length is 4.0 cm, not 3.3 cm. Not sure how you got your lengths.
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I thought here that the report wanted us to find the lengths in between the rubber bands on the line after we type end, so that is what those number are. I may have typed the data in wrong for the questions. The line after the 3.3, 3.8 etc. is the numer of the rubber band from which the in between rubber bands correspond to for the length in between band 1 and 2 was 3.3, which is what I thought the question to be.
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** #$&* Distances between ends when supporting 2 dominoes **
1cm, 5.2cm
1cm, 5.4cm
1cm, 5.2cm
1cm, 5.3cm
1cm, 5.2cm
1cm, 5.3cm
These are the measurements of the rubber bands with the weight of two dominoes.
** #$&* Lengths when supporting 4, 6, ... dominoes: **
5.7cm, 5.8cm, 5.6cm, 5.8cm, 5.6cm, 5.7cm
4
6.0cm, 6.3cm, 6.2cm, 6.3cm, 6.3cm,6.1cm
6
6.6cm, 6.9cm, 6.7cm, 6.8cm, 7.0cm, 6.7cm
8
End
This is the data of 4 six and 6 dominoes, I stopped at eight dominoes becuae my weakest rubber bands had reached more than 30% of their original length
** #$&* Your table of force in Newtons vs. length in cm for all rubber bands **
5.0cm, 5.1cm, 5.0cm, 4.9cm, 5.1cm, 4.9cm, .19
5.2cm, 5.4cm, 5.2cm, 5.3cm, 5.2cm, 5.3cm, .38
5.7cm, 5.8cm, 5.6cm, 5.8cm, 5.6cm, 5.7cm, .76
6.0cm, 6.3cm, 6.2cm, 6.3cm, 6.3cm, 6.1cm, 1.14
6.6cm, 6.9cm, 6.7cm, 6.8cm, 7.0cm, 6.7cm, 1.52
Lengths look Ok here. Not sure what happened earlier, but you're OK now.
The rubber bands should actually be longer than reported; possibly you used different rubber bands or you used a printed-out ruler that printed too long. Not a problem, as long as you use the same-sized ruler for subsequent experiments.
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Yeah, I use the printed out ruler from the rulers website for all of my labs. If i need to obtain another I can. :)
No problem; just be sure you use the same ruler when you use these rubber bands in later experiments.
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End
each column above is the lenght of the rubber bands 1, 2, 4, 6, & 8
(columns are in that order 1 being the first column 8 being the fifth column) after the dominoes have been placed in the bags. at the end of each column is the total downward force exerted by gravity by the dominoes. So for the first column the lengths are for 1 dominoe with a force of .19, the second is the lenght after two dominoes with a force .19*2=.38, third lenght after four dominoes .19*4 =.76and so on.
** #$&* Describe the graph of your first rubber band **
increasing at an increasing rate
increasing at an increasing rate
increasing at an increasing rate
Increasing at an increasing rate
increasing at an increasing rate
increasing at an increasing rate
End
I think that the force, on the vertical axis, put on the rubber bands was increasing by the addition of each domino, The length, on the horizontal axis was increasing due to the addition weight, So all of the graph show an increase at an increasing rate throughout.
Here is the table for Force vs Length of my rubber bands for the first four of one dominoe
5.7, .19
5.8, .38
5.6, .57
5.8, .76
I don't see a rubber band on your table that corresponds to these lengths. Your table looks fine; but here you're reporting a rubber band that doesn't change its length much and at one point actually gets shorter at the force increases.
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There was a part in the lab...I copied and pasted it here to clarify:
If you haven't already done so, include in your report a table of your data for force vs. length for each of the four selected rubber bands.
Think the table should have had lengths Vs force, so I think I should have chosen one length and the amount of force that the lenght corresponds to....I so I think that the tabe should be more like this....
This data is taken from the table of force in newtons vs length above. One length from each of the first row
and the force that corresponds to it obtained by the addition of the dominoes. Length are in the first row and force is in the second
5.0, .19
5.2, .38
5.7, .76
6.0, 1.14
6.6, 1.52
This looks good; it's consistent with your previously reported data.
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Tables for the additional dominoes are in the same format with the force in the y column and the lenght in the x column of the table.
** #$&* The tension force in your first rubber band at length 9.8 cm: **
1.6 newtons
All of your rubber bands report forces greater near 1.6 Newtons when their lengths are still less than 7 cm. This isn't consistent with your table.
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The question asked this:
Estimate the force in Newtons corresponding to a length of 9.8 cm and report the number in the first line of the box below
So, I estimated from my graph what the tension in newtons would be from the length of 9.8, I thought that was what the question was here. I put in m table that the lenght of the first rubber band was about 5.0 with one dominoe, so the force was .19 newtons, for the second line of my table I put a lenght of 5.2, with the addition of a dominoe so the force was .38 and so on. I am not sure if that is right, so I may be confused. :)
I believe you sketched a graph for each domino. Your graph would be based on lengths from about 5 cm to 7 cm, as you measured them with your printed-out ruler.
The 9.8 cm length is well beyond the 5 to 7 cm range, but your data points would indicate some sort of straight line or curve. To estimate the force at the 9.8 cm length you would need to make a reasonable extension of this curve, until it reaches at least the 9.8 cm coordinate; from this extended curve you would then be able to estimate the force corresponding to this length.
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revisison to the revision
If the length is 9.8cm I think that he force in newtons will be about 1.86
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** #$&* The length of your first rubber band when tension is 1.4 N: **
9cm
All your rubber bands exert forces greater than 1.4 N before reaching length 7 cm.
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Ok, I also obtained this from the graph I drew, because none of the tension that I calculated were 1.4, so Ilooked at the graph to see what length would correspond to a force of 1.4. I thought it wanted us to do it this way from the question, but I could be misinterpreting the questions.
That's the right thing to do, but all of your rubber bands exert forces exceeding 1.4 Newtons a lengths less than 7 cm. At length 9 cm it seems the forces would all be nearer 3 Newtons than 1.4 Newtons.
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revisison to revision
ok, I think that when the force is 1.4, then the lenght will be somewhere in between 6.0(obtained from the first length when force is 1.14) and 6.6(obtained from the first data point when force is caculated to be 1.52). So I think that the length will be about 6.4 cm according to the graph.
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** #$&* 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, .30, .60, 1.10, 1.50
The estimate of the curve of my graph was estimated in between each data point, between the first and second, third and fourth, fift and sixth. The force estimated according to this is close to the actual force exerted on each rubber band. For rubber band number two it is .08 difference, for number three it is .16, number four, .04, and number five .06 difference.
** #$&* The lengths predicted for forces .19 N, .38 N, .76 N, 1.14 N, etc. by the curve for your first rubber band; the deviations of your actual observations from these predictions: **
5.0cm, 5.3cm, 5.7cm, 6.2cm, 6.8cm
0.0cm, .01cm, 0.0cm, 0.2cm, 0.2cm
** #$&* The typical error you estimate when predicting force for a given length from your graphs: **
I have more faith in the values that I created in my table because that data is from actual measurements and calculations of the force. The data taken from the graph is more of an estimate than the data in the table.
I think the uncertainty would be .1 of a percent. .1/6.8= .01 * 100 =.1 percent
** #$&* The typical error you estimate when predicting length for a given force from your graphs: **
The uncertainty of the length would be about .2 percent .01/5.3=.0018 * 100= .2 percent
** **
about 2hours
** **
Your data look reasonable but your conclusions don't seem to match your data. See my notes and see if you can explain the discrepancies.
&#Please see my notes and submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end). &#
Your first correction looks good.
Your estimates based on your graphs still do not appear to correspond to your data. You correctly describe the process of making the estimates, but the estimates themselves do not seem to correspond to your data. You'll need to make similar estimates on later labs, so see if you can clarify this in another revision. If you can't do that in 15-30 minutes, send me a copy of those questions with your responses and ask me for a more detailed series of questions.
Your revisions look good. I don't think you were correctly oriented to the graph in your first submission; this corrects that.