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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 tape.
1) 7 inches, 20.562 seconds
2) 12 inches, 20.781 seconds
3) 20 inches, 21 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: ->->->->->->->->->->->-> (start in the next line):
I think I could estimate within .1 seconds and within 1.5 to 2 inches based on the times and position I recorded. If I took the difference
between each time and the distance covered in that time I
could roughly estimate a time or distance that fell
between each measurement.
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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):
The tape appears to be speeding up because the third
interval I recorded shows the tape moving 8 inches in
.219 seconds. The second interval shows it moving only 5
inches in the same time.
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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):
I would use the same method as with the tape. Compare
several different positions and times to determine if it
is covering more or less distance in the measured times.
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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):
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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):
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*#&!
&#Very good responses. Let me know if you have questions. &#