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course Phy 232
Question: This question, related to the use of the TIMER program in an experimental situation, is posed in terms of a familiar first-semester system.
Suppose you use a computer timer to time a steel ball 1 inch in diameter rolling down a straight wooden incline about 50 cm long. If the computer timer indicates that on five trials the times of an object down an incline are 2.42sec, 2.56 sec, 2.38 sec, 2.47 sec and 2.31 sec, then to what extent do you think the discrepancies could be explained by each of the following:
The lack of precision of the TIMER program.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I think we could partially attribute the discrepancies to the lack of precision of the TIMER program, as it does not seem to be extremely consistent in collecting data. There is a reasonably large range of data. To compensate, more trials should be taken.
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The uncertain precision of human triggering (uncertainty associated with an actual human finger on a computer mouse)
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I feel like human error is typically, but not always, more to blame for minor errors, especially when timing is involved. Perhaps the person had different reaction times or even multiple individuals were used to time. To increase accuracy, the same person should be timing, and attempting to keep everything as accurate as possible.
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Actual differences in the time required for the object to travel the same distance.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I dont think there were actual differences in the time required. If there were, they were very minute and would most certainly not account for the large differences in data.
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Differences in positioning the object prior to release.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I would like to assume that this was a controlled factor and that the ball was placed in some sort of secure starting position, but if it wasnt this would be a fairly large factor in the discrepancies in data as a shorter distance will result in a shorter time, regardless of anything else occurring.
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Human uncertainty in observing exactly when the object reached the end of the incline.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
As stated before, human error is almost always a factor of data discrepancies as it is out of our control in most cases. Again, reaction time can change from time to time, especially if different users took the data.
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Question: How much uncertainty do you think each of the following would actually contribute to the uncertainty in timing a number of trials for the ball-down-an-incline lab?
The lack of precision of the TIMER program.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I think the lack of precision of the TIMER program would only end up accounting for a small portion of the uncertainty: 5-10%
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The uncertain precision of human triggering (uncertainty associated with an actual human finger on a computer mouse)
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Uncertain precision of human triggering would account for a decent amount of the uncertainty: 25%
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Actual differences in the time required for the object to travel the same distance.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I really dont think this factor should account for any of the uncertainty, but there is always a small chance that times differ by small amounts: 1%
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Differences in positioning the object prior to release.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Differences in positioning the object prior to release could have easily effected the overall accuracy: 25%
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Human uncertainty in observing exactly when the object reached the end of the incline.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I think observing the object reaching the end, reacting, and clicking end time would have caused a significant delay in data taking: 30-35%
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Question: What, if anything, could you do about the uncertainty due to each of the following? Address each specifically.
The lack of precision of the TIMER program.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
To compensate for the possible lack of precision of the TIMER program, we could take additional trials so that our ultimate average was more accurate.
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The uncertain precision of human triggering (uncertainty associated with an actual human finger on a computer mouse)
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
The same person should be in charge of clicking the computer mouse, as it is likely that their numbers will remain the most consistent.
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Actual differences in the time required for the object to travel the same distance.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
There is little we can do to limit this uncertainty besides make sure all constant variables are actually kept constant.
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Differences in positioning the object prior to release.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
We could create some sort of mechanism to hold the object in place before its release. That way, it is guaranteed to be released at the same location each trial.
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Human uncertainty in observing exactly when the object reached the end of the incline.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Again, the same person should be observing the ball reach the bottom each time and they should be the ones stopping the timer, as they will have the quickest reaction time.
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&#This looks good. Let me know if you have any questions. &#
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