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Phy 121
Your 'cq_1_08.1' 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_08.1_labelMessages **
A ball is tossed upward with an initial velocity of 25 meters / second. Assume that the acceleration of gravity is 10 m/s^2 downward.
What will be the velocity of the ball after one second?
answer/question/discussion: ->->->->->->->->->->->-> :
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25m/s - 10m/s/s after 1 sec = 15m/second
• What will be its velocity at the end of two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
25m/s - 10m/s/s - 10m/s/s = 5m/second
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• During the first two seconds, what therefore is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
25m/s + 5m/s / 2 = 15m/second
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• How far does it therefore rise in the first two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
= 20m/s / 2sec = 10m
average velocity (25m/s + 5m/s) / 2 = 15m/sec
displacement 15m/s / 2s =7.5m/sec
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If I move at 60 mph for 4 hours, do I go 15 miles (corresponding to 60 mph / (4 hr)) or 240 miles?
If you're moving at an average 15 m/s then you go an average of 15 meters every second. If you do this for 2 seconds, how far do you go?
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What will be its velocity at the end of a additional second, and at the end of one more additional second?
answer/question/discussion: ->->->->->->->->->->->-> :
3 seconds= -5m/s
4 seconds = -15m/s
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• At what instant does the ball reach its maximum height, and how high has it risen by that instant?
answer/question/discussion: ->->->->->->->->->->->-> :
the ball reaches its maximum height at v = 0.
v^2 - vo^2 / 2a
= (25m/s)^2 / 2(-10m/s) = 31.25m
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• What is its average velocity for the first four seconds, and how high is it at the end of the fourth second?
answer/question/discussion: ->->->->->->->->->->->-> :
(25+-5) / 2 =10m/s
The change in clock time is 4 seconds
= 10m/s / 4s = 2.5m/sec (displacement)
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This also needs to be revised.
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*#&!
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Good, but you need to think carefully about what your results mean. Two of your results are incorrect and need to be revised.
&#Please see my notes and submit a copy of this document with revisions, comments and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes. &#
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