#$&*
Phy 201
Your 'cq_1_02.2' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** **
The problem:
A graph is constructed representing velocity vs. clock time for the interval between clock times t = 5 seconds and t = 13 seconds. The graph consists of a straight line from the point (5 sec, 16 cm/s) to the point (13 sec, 40 cm/s).
• What is the clock time at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The midpoint clock time is 9sec. (13sec + 5sec / 2= 9sec).
#$&*
• What is the velocity at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The velocity is 28cm/s ((16cm/s + 40cm/s )/2= 28cm/s).
#$&*
• How far do you think the object travels during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
440cm.
40cm/s *13s = 520cm= total travel in 13 s.
16cm/s *5s= 80cm= total travel in 5 s.
520 cm - 80cm= 440cm
#$&*
@& The object is not moving at 40 cm/s for 13 seconds, nor is it moving at 16 cm/s for 5 seconds.
Among other things you don't have no information about the interval from t = 0 sec to t = 5 sec.
The interval for which we have information lasts 8 seconds. The maximum speed is 40 cm/s. So the distance can't be over 320 cm.*@• By how much does the clock time change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
8 seconds. (13s - 5 s).
#$&*
• By how much does velocity change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
Velocity changes by 24cm/s ( 40cm/s - 16cm/s.)
#$&*
• 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/s - 16cm/s) / (13sec-5sec) = (24cm/s) / 8 = 3cm/sec.
#$&*
@& Right procedure. There are a couple of errors in detail:
13 sec - 5 sec = 8 sec, not 8.
The units of your result will therefore not be cm/s.*@
• What is the rise of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The rise of the graph is 24. (40-16=24)
#$&*
• What is the run of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The run of the graph is 8 (13-5= 8)
#$&*
• What is the slope of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The slope is 3 (24/8=3).
#$&*
@& The rise, the run and the slope all have units, which need to be included.*@
• 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 object is accelerating at an average of 3cm/sec.
#$&*
@& Good except fo the units, which are not correct.*@
• What is the average rate of change of the object's velocity with respect to clock time during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The average rate of change therefore is also 3cm/s.
#$&*
@& Good except fo the units, which are not correct.*@
*#&!
@& You have most of the right ideas, but there are errors in detail.
I believe you will be able to correct them without much difficulty. However limit yourself to 15 minutes, then if necessary ask questions.
&#Please see my notes and, unless my notes indicate that revision is optional, submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes.
If my notes indicate that revision is optional, use your own judgement as to whether a revision will benefit you. &#
*@