Phy 121
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: ->->->->->->->->->->->-> (start in the next line):
We don't know the exact distance traveled or how long that it took. I think that I remember reading that an object ended with normally double its average velocity this is a special condition when acceleration is uniform and initial velocity is zero
so I'm thinking that the average would be 5 cm/sec. I guess another way is thinking about is by taking an average of the two numbers which would give us 7 cm/sec. So maybe a good answer will be between 5 and 7 cm/sec.
your reasoning on the 7 cm/s is correct
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Without further information, why is this just a guess?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
This is a guess because we don't know the exact distance or time involved so we can't plug the numbers into the formula (change in distance over change in time).
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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: ->->->->->->->->->->->-> (start in the next line):
It takes 3 sec to go from 4 cm/sec to 10 cm/sec so 3 sec for a change in speed of 6 cm/sec.
With this in mind, I'm guessing that in 3 sec. it traveled 6 cm + 8cm + 10 cm= 24 cm
not quite; check the link given at the end
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At what average rate did its velocity change with respect to clock time during this interval?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
It speeds up by 6 cm/sec in 3 sec. so I'm assuming that it is increasing its speed my 2 cm/sec each sec.
Very good.
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15-20 min.
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2-3-10 at 6:45 p.m.
&#Please compare your solutions with the expanded discussion at the link
Solution
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