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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 clock times are 5 s and 13 s, not 6 s and 13 s. Good reasoning, though, and your result isn't far off.*@
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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
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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
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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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@& Very good.
That first clock time was 5 s, not 6 s. However your solution is correct throughout if the initial time is 6 s.*@