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course Phy 232
Comment on your experience with the three lab exercises you encountered in this assignment or in recent assignments. I was fairly impressed by the timer program and the thoroughness of the pendulum exercise. At this point I dont really understand the point of these experiments considering that I studied harmonic motion in the first semester of physics, but Im sure it will become apparent later on.
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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 dont think that the Timer program has any problems in itself. I believe that the error probably come from the human.
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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 believe that most of the discrepancies can be explained by human error. It is very difficult to be precise with the muscle movements of the hand.
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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
It is very unlikely that different results would be observed if the same conditions were kept constant. Any difference in the time required for the object to travel would have had to come from an initial accidental force.
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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
It is possible that different positions could yield different times. The forces acting on the object would cause it to move faster or slower if it was started closer to the bottom of the incline or farther away.
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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?
It is very possible that error could come from this as well. It is hard to gauge the exact position of an object in fast motion. The observer could be off by several milliseconds.
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
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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
Very little uncertainty would be associated with the Timer program
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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
Very little uncertainty would be associated with the actual triggering of the finger. It would be a miniscule amount at most.
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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
If conditions were kept constant there would be very little uncertainty associated with this
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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
This could potentially yield a lot of uncertainty. The effects of gravity are magnified when there is more time to work on an object.
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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
A lot of uncertainty could be associated with this. Human error could potentially be very significant.
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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
There is nothing to be done about this unless you could find a better timer program.
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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
There is nothing to be done about this. The precision of the human hand is set by genetics.
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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
Make sure that conditions remain as constant as possible. Try not to move or adjust the apparatus between runs.
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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
Make a mark so that you are sure to start from the same place every time.
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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
There is not really anything that can be done about this either except to be very focused and to throw out any measurements that are known to have been off.
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