#$&*
PHY 231
Your 'cq_1_02.2' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** **
The problem:
A graph is constructed representing velocity vs. clock time for the interval between clock times t = 5 seconds and t = 13 seconds. The graph consists of a straight line from the point (5 sec, 16 cm/s) to the point (13 sec, 40 cm/s).
• What is the clock time at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
(5s + 13s) /2
= 9s
#$&*
• What is the velocity at the midpoint of this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
(16 cm/s + 40 cm/s)/2
= 28 cm/s
#$&*
• How far do you think the object travels during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
8s * 28 cm/s
= 224 cm
#$&*
• By how much does the clock time change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
8 sec
#$&*
• By how much does velocity change during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
24 seconds
#$&*
@& cm/s, not s, as you obviously know.*@
• 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):
aBar = 24cm/s / 8s
=3 cm/s/s
#$&*
• What is the rise of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
24 cm
@& The rise is 24 cm/s, not 24 cm. Do be sure you understand this.*@
#$&*
• What is the run of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
8 s
#$&*
• What is the slope of the graph between these points?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
3 cm/s/s
#$&*
• 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):
It tells us the object is uniformly accelerating by 3 cm/s/s. This means the velocity will increase by 3 cm/s every second ( a constant rate giving us the straight line in the graph). We know the velocity change and time are uniform, but the final variable displacement is not. This was only briefly mentioned above for the distance of 224 cm; however, this will increasingly increase on the graph as the line gets higher. (Displacement is the area below the Velocity vs. Time curve/line.)
#$&*
• What is the average rate of change of the object's velocity with respect to clock time during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
aBar = 24cm/s / 8s
=3 cm/s/s
#$&*
** **
10 minutes or so
** **
14:52
&#Good work. See my notes and let me know if you have questions. &#