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phy121
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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The problem:
You don't have to actually do so, but it should be clear that if you wished to do so, you could take several observations of positions and clock times. The main point here is to think about how you would use that information if you did go to the trouble of collecting it. However, most students do not answer these questions in terms of position and clock time information. Some students do not pause the video as instructed. To be sure you are thinking in terms of positions and clock times, please take a minute to do the following, which should not take you more than a couple of minutes:
• Pick one of the videos, and write down the position and clock time of one of the objects, as best you can determine them, in each of three different frames. The three frames should all depict the same 'roll' down the ramp, i.e. the same video clip, at three different clock times. They should not include information from two or more different video clips.
• For each of the three readings, simply write down the clock time as it appears on the computer screen, and the position of the object along the meter stick. You can choose either object (i.e., either the pendulum or the roll of tape), but use the same object for all three measurements. Do not go to a lot of trouble to estimate the position with great accuracy. Just make the best estimates you can in a couple of minutes.
Which object did you choose and what were the three positions and the three clock times?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
I chose to look at video 3 and look at the pendulum. The 3 positions I saw were at 6, 14 and 18 inches. The times for those were 29.234, 29.453, 29.671 respectively.
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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: ->->->->->->->->->->->-> (start in the next line):
you can determine the speed of the pendulum or the object between certain intervals. From my observations, the videos weren’t as clear as I would hope, but if they were crytal clear, you could determine the positons at certain intervals. But then there is the human error effect, where you read the object on the tape? The beginning of it? The middle of the object? The end of the object? You would have to determine that before hand and keep it constant through each reading. I took the nearest inch on the reading to make the reading a bit easier and I read it from the middle of the pendulum.
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• 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?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
You take the distance traveled through an interval and the time it took to go through that interval and calculate the speed. If you do this for each interval, lets say every 3 inches, you can determine whether or not it is slowing down or speeding up, whether it’s a constant speed.
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&#Very good responses. Let me know if you have questions. &#
What measurable quantities change when we change the slope of the incline?
your best answer ->->->->->->->->->->->->
Measurable quantities that chance when the slope of the incline changes is the speed or velocity.
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