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phy 201
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.
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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):
Quantity A is displacement in cm and quantity B is time in seconds. Rate would be change in A with respect to change in a B, therefor it would be (20cm-10cm)/(9s-4s)= 10cm/5s= 2cm/s
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Good, but technically quantity A is position. Displacement is defined to be change in position.
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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):
Quantity A is the changing velocities in cm/s, and quantity B is the time in s. Therefore, the average should be change in quantity A with respect to change in quantity B. So, (40cm/s-10cm/s)/(3s)=10cm/s^2 which I believe to be a measure of acceleration.
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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):
The position change is 50cm, because average rate of change=change in A with respect to change in B. Therefore 5cm/s=x/10s, solve for x by multiplying both sides by 10s.
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Good, but better conceptually to think in terms of average rates:
ave rate of change of position with respect to clock time = change in position / change in clock time so
change in position = average rate ... * change in clock time
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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):
memorization and practice
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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):
Average rate of change is the change in one quantity with respect to another quantity.So you could measure the change in position with respect to a change in time period. I will remember this with practice.
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Your work looks good. See my notes. Let me know if you have any questions.