course Phy 241
I sent a message to let you know that I did not receive feedback for error analysis part II. This lab deals with the results of the earlier TIMER experiment. The message that you sent is included below and I am not sure what it is referring to.
Error_Analysis_Part2course Phy 241
Your work has been received. Please scroll through the document to see any inserted notes (inserted at the appropriate place in the document, in boldface) and a note at the end. The note at the end of the file will confirm that the file has been reviewed; be sure to read that note. If there is no note at the end, notify the instructor through the Submit Work form, and include the date of the posting to your access page.
The lab Error Analysis II did not show up on my access page. I submitted it July 1.
Apparently I didn't include my critiques of those labs when I posted files. It should now be posted.
Send me a copy of the following, and your answers to the questions:
Rubber band length, the number of dominoes supported at this length, the mean and the standard deviation of the sliding distance in cm, and the energy associated with the stretch, for each set of 5 trials:
8.6,2,1.52,.2387,.5776
9,4,1.28,.1304,.9728
9.6,6,1.88,.0837,2.1432
9.9,8,6.12,.6834,9.3024
10.5,10,9.3,1.286,17.67
For each of your five lines of data:
What average force was exerted by the rubber band, and how did you determine this?
Through what distance did the rubber band exert its force?
What therefore is the product of the average force and the distance through which this force was exerted?
For this first line 8.6,2,1.52,.2387,.5776:
I took the rubber band length of 8.6cm which is what the stretch is at 2 dominoes which exerts a force of .38N. I took the mean distance of 1.52cm and multiplied it by .38N which gives me .5776N * cm.
Wouldn’t my average force be the .38N, and the average distance is the mean of 1.52cm?
Not quite. The .38 N of force was not being exerted while the dominoes were sliding. For most of the slide the rubber band wasn't doing anything.
The distance you need to use is the distance through which the rubber band actually exerted the force. This is the distance between the 8.6 cm length and the length at which the rubber band goes 'slack', probably somewhere around 7.8 cm (give or take a few cm).
The average force isn't .38 N. The force over this displacement is .38 N when you release the rubber band, but the force drops to 0 by the time the rubber band first goes slack. The change in force is more or less linear with distance, so you can average the .38 N and the 0 N to get .19 N.
This is what you multiply by the .8 cm or so over which the rubber band exerts the force.
For your last line, representing 10 dominoes, the max force would be 1.9 N. The average force would be about .85 N, and the rubber band exerts its force through a displacement of about 2.7 cm (assuming that the length at which it ceases to exert a force is 7.8 cm).
Can you send me a correction of this information, and an outline of how this changes the rest of your analysis? Alternatively you can just submit the form again, starting from this point."
Your work has not been reviewed.
Please notify your instructor of the error, using the Submit Work form, and be sure to include the date 07-07-2006.
Good. Let me know if you have questions.