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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.
** CQ_1_00.1_labelMessages **
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: ->->->->->->->->->->->-> scussion (start in the next line):
roll of tape
4.75 at 40.468 seconds
9.25 at 40.687 seconds
13.5 at 40.906 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 an
explanations of the basis for your estimate: Why did you make the estimate you did?
answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):
From the video the position can be obtained with in forths of inches and clock times can be deterimined within in .001 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: ->->->->->->->->->->->-> scussion (start in the next line):
If I was using just the data, as the distance from the intial position increased, if the time between positions decreased the tape would be on
an incline speeding up. If dthe time between positions increased the tape would be on an incline slowing down.
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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: ->->->->->->->->->->->-> scussion (start in the next line):
If I was using just the data, as the distance from the intial position increased, if the time between positions decreased the pendulum would
be on be speeding up, and if time between positions were increasing the pendulum would be slowing down.
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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: ->->->->->->->->->->->-> scussion (start in the next line):
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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: ->->->->->->->->->->->-> scussion (start in the next line):
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&#This looks good. Let me know if you have any questions. &#