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phy 201
Your 'cq_1_02.2' 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:
A graph is constructed representing velocity vs. clock time for the interval between clock times t = 5 seconds and t = 13 seconds. The graph consists of a straight line from the point (5 sec, 16 cm/s) to the point (13 sec, 40 cm/s).
• What is the clock time at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
midpoint coordinate (9.5, 28 )
Clock time (X1 + X2) / 2 = (6 + 13) / 2 = 9.5
The clock time at the midpoint is 9.5 sec
the initial instant is 5 sec, not 6 sec; but right approach
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• What is the velocity at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Midpoint coordinate (9.5, 28)
Velocity (Y1 + Y2) / 2 = (16 + 40) / 2 = 28
The velocity at the midpoint is 28 cm/s
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• How far do you think the object travels during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
I have the average velocity, 28 cm/s and the time interval, 7 seconds, so I can solve for distance
28 cm/s = d / 6 sec
28 cm/s * 7 sec = d
196 cm
good, but note that time interval is 8 sec
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• By how much does the clock time change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
7 seconds
X2 -X1 = clock interval
13 s - 6 s = 7 seconds
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• By how much does velocity change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
24 cm/s
Y2 - Y1 = change in velocity
40 - 16 = 24 cm/s
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• What is the average rate of change of velocity with respect to clock time on this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Average rate of change = change in velocity / change in time = 24 cm/s / 7 sec = 3.43 cm/s/s
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• What is the rise of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Y2 - Y1 = rise
40 - 16 = 24
these quantities all have units; similar note for your next few answers
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• What is the run of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
X2 - X1 = run
13 - 6 = 7
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• What is the slope of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
slope = rise/run
24/7 = 3.43
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• What does the slope of the graph tell you about the motion of the object during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The slope of the graph tells me that the object is increasing in velocity.
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• What is the average rate of change of the object's velocity with respect to clock time during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Average rate of change = change in velocity / change in time = 24 cm/s / 7 sec = 3.43 cm/s/s
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20 minutes
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You misread the initial clock time and left units off of some calculations; otherwise fine. No need for revision.
&#See any notes I might have inserted into your document. If there are no notes, this does not mean that your solution is completely correct.
Then please compare your solutions with the expanded discussion at the link
Solution
Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified.If your solution is completely consistent with the given solution, you need do nothing further with this problem. &#