#$&*
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.
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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?
13 - 5 = 8 and half of 8 is 4. Add 4 to 5 and 9 seconds is your midpoint.
• What is the velocity at the midpoint of this interval?
Since we are given that the graph is a straight line we can find the slope and in this case it’s 3. Since we now know that the midpoint is 4 seconds away from the beginning we multiply 3 * 4 = 12 and add it to the 16 to get 28 cm/s.
• How far do you think the object travels during this interval?
5 16
6 19
7 22
8 25
9 28
10 31
11 34
12 37
13 40
If you sum of the y-values you’ll get the distance traveled which is 252 cm.
@& During each second the object travels further than you have indicated. Your numbers coincide with the minimum speed on each interval, not the average speed.
*@
@& You list 13 distances. There are only 8 one-second intervals.*@
• By how much does the clock time change during this interval?
13 - 5 = 8 seconds.
• By how much does velocity change during this interval?
40 - 16 = 24 cm/s (total change in velocity.)
• What is the average rate of change of velocity with respect to clock time on this interval?
the average rate of change between the two points is (40 - 16) / (13 - 5) = (24 / 8) = 3 cm / s
• What is the rise of the graph between these points?
The rise is 24 (40 - 16)
• What is the run of the graph between these points?
The run is 8 (13 - 5)
• What is the slope of the graph between these points?
The slope is 3 (24 / 8)
• What does the slope of the graph tell you about the motion of the object during this interval?
The object is moving at a constant rate.
@& The object isn't moving at a constant rate. It's moving faster and faster.*@
• What is the average rate of change of the object's velocity with respect to clock time during this interval?
Since the object is always increasing by the same velocity it’s rate doesn’t change. The velocity’s rate of change is zero.
@& The velocity would not change from 16 m/s to 40 m/s if the rate of change of the velocity was zero.*@
@& `c022*@