phy121
Your 'cq_1_02.1' 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:
A ball starts with velocity 4 cm/sec and ends with a velocity of 10 cm/sec.
What is your best guess about the ball's average velocity?
answer/question/discussion:
My best guess would be to add the two velocities and divide by two, giving us an average velocity of 7.
Without further information, why is this just a guess?
answer/question/discussion:
This is just a guess, because we dont know anything about the incline it is on. For instance, it may or may not be consistent.
If it takes 3 seconds to get from the first velocity to the second, then what is your best guess about how far it traveled during that time?
answer/question/discussion:
Using d=rt, if the avg velocity is 7cm/sec and the time interval is 3 seconds, then it traveled 21 seconds.
At what average rate did its velocity change with respect to clock time during this interval?
answer/question/discussion:
The rate changed 6 cm/sec in 3 seconds, so the average rate of change would be 2cm/sec.
6 / 3 = 2, of course, but (6 cm/s) / (3 s) is not 2 cm / sec. The units of your answer do not match the units of the calculation.
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7 minutes
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Good, almost everything is correct and your reasoning is excellent and well-documented.
Your only error was a units error, which you need to address. The detailed solution is worth a look om amy case:
&#At least part of your solution does not agree with the solution and comments given at the link below. You should view the solution at that link and self-critique as indicated there.
Solution
This link also expands on these topics and alerts you to many of the common errors made by students in the first part of this course. &#