Phy231
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.
** **
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):
13sec - 5sec= 8sec/2 = 4sec The midpoint of the line will be at the clock time of 9sec because 5sec + 4sec= 9sec
#$&*
What is the velocity at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
40cm/sec - 16cm/sec= 24cm/sec /2= 12cm/sec So the midpoint of the line for velocity is 12cm/sec +16cm/sec= 28cm/sec
#$&*
How far do you think the object travels during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Well it increases its avg velocity by 12cm/sec in about 8sec. So 12cm/sec /8sec= 1.5cm
Its velocity increases from the initial to the final velocity; its average velocity is what it is, 28 cm/s for this interval. However the average velocity isn't involved in calculating the change in velocity.
#$&*
By how much does the clock time change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
8sec
#$&*
By how much does velocity change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
12cm/sec
#$&*
What is the average rate of change of velocity with respect to clock time on this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
40cm/sec - 16cm/sec= 24cm/sec 24cm/sec/8/sec= 3cm So the average rate of change was approximately 3cm/sec.
#$&*
What is the rise of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
40cm/sec - 16cm/sec= 24cm/sec is the rise
#$&*
What is the run of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
13sec -5sec= 8sec is the run
#$&*
What is the slope of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
rise/run= 24/8= 3 is the slope
These quantities have units.
#$&*
What does the slope of the graph tell you about the motion of the object during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
That it is slowly rising from bottom left to upper right, the line is positive.
#$&*
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):
Already answered this question......see previous answer
#$&*
** **
20min
** **
2/11/10 11am
You have a couple of errors, which you should correct. It shouldn't be difficult to make the corrections.
&#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. &#