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:
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Write down the position and clock time of one of the objects, as best you can determine them, in each of three different frames. This means that for each of the three readings, you just 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, 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: I chose the pendulum and the three positions were : 0 at 59.140 sec , 1' at 59.687 sec, 2' at 60.343 seconds
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 such observations:
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If you did take observations of positions and clock times, how accurately do you think you could determine the positions, and how accurately do you think you would know the clock times?
answer/question/discussion: Given the clarity of the video it would be difficult to see the numbers on the ruler. It would be hard to get more accurate than an inch. Anything smaller than an inch would be difficult to observe. Also, there is a delay in the pause/play feature of the media player which gives a blur to the moving objects and clock.
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How can you use observations to determine whether the tape rolling along an incline is speeding up or slowing down?
answer/question/discussion: When both objects are released the pendulum is ahead of the tape, about half way they are in roughly the same position, and at the end the tape the tape is slightly ahead of the pendulum.
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How can you use your observations to determine whether the swinging pendulum is speeding up or slowing down?
answer/question/discussion: the pendulum is speeding up before the half-way point and slowing down after the half-way point because gravity is pulling down at the fixed point of the pendulum.
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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:
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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:
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11 minutes
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&#Your work looks good. Let me know if you have any questions. &#
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.
** **
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:
Write down the position and clock time of one of the objects, as best you can determine them, in each of three different frames. This means that for each of
the three readings, you just 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, 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: I chose the pendulum because it was easier to follow and had less motion blur for getting readings. The three postions and clock
times where 5 at 59.46, 9 at 59.68, and 15 at 59.90.
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 such observations:
If you did take observations of positions and clock times, how accurately do you think you could determine the positions, and how accurately do you think you
would know the clock times?
answer/question/discussion: The accuracy of both the postions and clock times are accurate enough to conduct most experiments. When dealing with motion and
time it is hard to be exact and there is always room for a small amount error. They key is to keep the amount of error to a minimum to get the best possible
results from your observations. Even though the video wasn't the best quality, it was suffient enough to get fairly accurate readings.
How can you use observations to determine whether the tape rolling along an incline is speeding up or slowing down?
answer/question/discussion: The amount of distance traveled would increase more rapidly as time increases if the tape is speeding up. If it was slowing down
the distance traveled would be decreasing between the ticks of time as it increases.
How can you use your observations to determine whether the swinging pendulum is speeding up or slowing down?
answer/question/discussion: Basically, the same answer as above. If distance traveled is increasing between ticks of the clock than you are speeding up and
if the distance traveled between ticks decreases or rather increases less distance than it did from previous ticks than you are slowing down.
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: Basically you would have to collect lots of data and compared distant traveled versuses time passed. You will see increases in
distances traveled and then you will start to see less increases and then you will see distance traveled between to ticks become shorter. The shorter
distances traveled indicate that you are slowing down and thus at the point you see a decrease in distance traveled you have found the point at which the
pendulum began to slow down.
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: Again you will have to college lots of data to accurately determine how much you are speeding up or slowing down but you can take
your data and calculate the differences in distance traveled between ticks of time. You could enter your data in a graphing calculator and graph a line or
curve to represent your data and see if the rate is speeding up, constant, or slowing down.
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30mins
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&#This looks good. Let me know if you have any questions. &#