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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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?
Video #3 the pendulum
position #1 4in 29.234
position #2 16in 29.562
position #3 18 in 29.671
answer/question/discussion:
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? the positions were be estimates because the pendulum obscures the tape measure increments smaller than the inch marks as well as the blurr does not allow for an accurate reference point. this might reflect some error in calculations. the clock time is very visible
Give a reasonable numerical answer to this question (e.g., positions within 1 meter: a meter would allow gross location without attention to detail
within 2 centimeters: If the hash marks were darkers per cm, id of the location may be possible. therefore the frame #1 would be 10ish, frame #2 would be around 41 and frame #3 would be 46 cm-ish. I used a cm tape measure to compare inch harsh marks to cm at a distance similar to the camera's length
within 3 inches: this length would definitely be easy to id on the tape measure but not provide a closer margin of error
clock times within 3 seconds: 3 seconds would not reveal anything since all three frames were within .6 seconds from start to finish
or within .002 seconds: frame 1 occurred approx 0.3 seconds of frame2 and frames 2 occurred 0.1 sec from frame 3 thus .002 seconds allows more detail to the spread of times
or within .4 seconds: as axplained in the .002 example, .4 seconds would not show much difference at all in the difference in time, etc.).
You should include an explanations of the basis for your estimate: yes in order to be reproducible, a scale system should be defined.
Why did you make the estimate you did? Without calculating each defference between frames, I rounded
answer/question/discussion:
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?
If acurate positions could be determined, then the time between equal intervals would demonstrate if the pendulum was speeding, slowing or unchanged
answer/question/discussion:
How can you use observations of position and clock time to determine whether the swinging pendulum is speeding up or slowing down?
a rough estimate of location may demonstrate the same behavior as the tape roll but the arch of the swing compared to a linear slope adds another factor
answer/question/discussion:
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?
I do not know
answer/question/discussion:
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? measure the time between each distance interval and compare
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1 hr
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&#Your work looks very good. Let me know if you have any questions. &#