Phy 121
Your 'cq_1_00.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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Which object did you choose and what were the three positions and the three clock times?
answer/question/discussion: ->->->->->->->->->->->-> :
Video 3
The tape –
29.015 seconds: 3 inches (about a half inch before pendulum)
29.453 seconds: 13 inches (exactly with pendulum)
29.67 seconds: tape at finish (pendulum about an inch or two behind)
In the following you don't have to actually do calculations with your actual data. Simply explain how you would use data of this nature if you had a series of several position vs. clock time observations:
• If you did use observations of positions and clock times from this video, how accurately do you think you could determine the positions, and how accurately do you think you would know the clock times? Give a reasonable numerical answer to this question (e.g., positions within 1 meter, within 2 centimeters, within 3 inches, etc; clock times within 3 seconds, or within .002 seconds, or within .4 seconds, etc.). You should include an explanations of the basis for your estimate: Why did you make the estimate you did?
answer/question/discussion: ->->->->->->->->->->->-> :
I would say my positions stated are within a half to a quarter inch of accuracy. The timing would be within .01 seconds of accuracy. I say this because I used the larger file and was able to make out the inches marks quite well and I have already been instructed that the clock was accurate within .01 of a second.
• How can you use observations of position and clock time to determine whether the tape rolling along an incline is speeding up or slowing down?
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I can use the clock to determine if the tape is taking faster or slower for every position and calculate out an answer.
• How can you use observations of position and clock time to determine whether the swinging pendulum is speeding up or slowing down?
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I would use the same approach as I did with the tape. Find the positions between clips and use the time to find out whether it is slowing down of speeding up.
• Challenge (University Physics students should attempt answer Challenge questions; Principles of Physics and General College Physics may do so but it is optional for these students): It is obvious that a pendulum swinging back and forth speeds up at times, and slows down at times. How could you determine, by measuring positions and clock times, at what location a swinging pendulum starts slowing down?
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If we take many clips of the pendulum and record the time and position, it would be possible to form a graph of the data. It will form a type of parabola for which we would know when the time speeds up and slows down.
very good
• Challenge (University Physics students should attempt answer Challenge questions; Principles of Physics and General College Physics may do so but it is optional for these students): How could you use your observations to determine whether the rate at which the tape is speeding up is constant, increasing or decreasing?
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When I look at the pendulum I know it speeds up and at some point around the mid point begins to slow down. The tape increases with the pendulum as it is speeding up but overtakes it as it continues to slow down. I would come to the conclusion that the tape is speeding up.
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30 minutes
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Excellent answers and insight.