PHY 201
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 the first video and the pendulum for this experiment. Here are my three positions and three clock times that corresponds:
1: approx. 9.5 inches and at 59.577 seconds.
2: approx. 5 inches and at 59.46 seconds.
3: approx. 15 inches and at 59.906 seconds.
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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 any explanations of the basis for your estimate: Why did you make the estimate you did?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Each time you stop the video and try to measure the object at the appropriate measurement, the object is right in front of the measuring device, so measuring has to be done by approximate. From the video, I could estimate the positions within 2 inches and also estimate the positions within 2 seconds. The problem is the ruler is behind the pendulum, which takes up about 2 inches and you have to count from the end to estimate the appropriate inch to where the pendulum is located. The timer gives the seconds done decimal and if you round off to the nearest whole number you could go either up or down, so that is why I chose to go with 2 seconds.
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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 can simply look at the positions and clock time to determine whether the tape is speeding up or slowing down. The faster it gets the less time it would take to go from one distance to another, and if it was declining it would take more time to travel from one distance to the other.
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• How can you use observations of position and clock time to determine whether the swinging pendulum is speeding up or slowing down?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Each time the pendulum swings back and forth, the slower it gets. I think when you let the pendulum go the speed is greater than it would be when it got to the other side.
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• 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?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Measuring the ends of where the pendulum stopped when it swung in the both directions, and measuring when the pendulum stopped approximately in the center and subtract the distances from both ends.
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• 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?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
By getting many measurements of time and length, and then taking the difference of them can let you see if the speed is constant, increasing, or decreasing.
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45 minutes
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&#Good work. Let me know if you have questions. &#
&#Your work is mostly correct, and I believe you will understand everything after reading the document in the link below. You will be directed to submit a revision; however unless you have questions or comments, the revision is not necessary. Just be sure you understand all the important details in the document. &#