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PHY 121
Your 'cq_1_01.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_01.1_labelMessages **
The problem:
Here is the definition of rate of change of one quantity with respect to another:
The average rate of change of A with respect to B on an interval is
average rate of change of A with respect to B = (change in A) / (change in B)
Apply the above definition of average rate of change of A with respect to B to each of
the following. Be sure to identify the quantity A, the quantity B and the requested
average rate.
If the position of a ball rolling along a track changes from 10 cm to 20 cm while the
clock time changes from 4 seconds to 9 seconds, what is the average rate of change of
its position with respect to clock time during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The change in position is 20-10=10 cm. The change in time is 9-4=5 sec. This means
that the average rate of change of position with respect to clock time is 10 cm/5 sec or
2 cm per second.
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If the velocity of a ball rolling along a track changes from 10 cm / second to 40 cm /
second during an interval during which the clock time changes by 3 seconds, then what is
the average rate of change of its velocity with respect to clock time during this
interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The change in rate is 40 cm/sec-10 cm/sec or 30 cm/sec. The change in clock time is 3
sec. If you divide 30 cm/sec by 3 sec, you will get 10 cm/sec change.
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Good, but 30 cm/s divided by 3 s gives you 10 (cm/s) / s = 10 cm/s^2.
*@
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If the average rate at which position changes with respect to clock time is 5 cm /
second, and if the clock time changes by 10 seconds, by how much does the position
change?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
If you have a change of 5 cm/sec over a period of 10 seconds, you have to multiply 5
cm/sec times 10 second to get a total of 50 cm change in position.
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You will be expected hereafter to know and apply, in a variety of contexts, the
definition given in this question. You need to know this definition word for word. If
you try to apply the definition without using all the words it is going to cost you time
and it will very likely diminish your performance. Briefly explain how you will ensure
that you remember this definition.
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
I have copied it in my notes and highlighted it with pink highlighter. The other way I
remember things is to repeat them out loud to myself until I remember it.
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You are asked in this exercise to apply the definition, and given a general procedure
for doing so. Briefly outline the procedure for applying this definition, and briefly
explain how you will remember to apply this procedure.
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
I generally first think of miles per hour. Then I replace miles with cm or mm or
whatever length is being worked with. Then I replace hour with seconds, if that is what
is in the problem. Then I plug in the numbers, so in the first problem, I was figuring
out cm/sec and the cm change was 20-10, with a change in time of 9-4 sec. This gave me
a problem of 10 divided by 5, or 2. If I use that as the basis, I can plug in the
information I have been given and decide if I need to add, subtract, multipy, or divide
to find the missing information.
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&#Good work. See my notes and let me know if you have questions. &#