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phy 201
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.
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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: ->->->->->->->->->->->-> :
aAve = (vf - v0) / `dt
-10 m/s/s = (vf - 25 m/s) / 1 s
-10 m/s = vf - 25 m/s
15 m/s = vf
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• What will be its velocity at the end of two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
-10 m/s/s = (vf - 25 m/s) / 2 s
-20 m/s = vf - 25 m/s
5 m/s = vf
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• During the first two seconds, what therefore is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve = (v0 + vf) / 2
vAve = ( 25 m/s + 5 m/s) /2
vAve = 30 m/s / 2
vAve = 15 m/s
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• How far does it therefore rise in the first two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve = `ds / `dt
15 m/s = `ds / 2 s
30 m = `ds
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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
-10 m/s/s = (vf - 25 m/s) / 3 s
-30 m/s = vf - 25 m/s
-5 m/s = vf
# 4 seconds
-10 m/s/s = (vf - 25 m/s) / 4 s
-40 m/s = vf - 25 m/s
-15 m/s = vf
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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 it height when the velocity reaches 0 m/s.
-10 m/s/s = (0 - 25 m/s) / `dt
-10 m/s/s * `ds = -25 m/s
`dt = 2.5 s
vAve = `ds / `dt
(v0 + vf) / 2 = `ds / `dt
(25 m/s + 0 m/s) / 2 = `ds / 2.5 s
12.5 m/s * 2.5 s = `ds
31.25 m = `ds
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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: ->->->->->->->->->->->-> :
-10 m/s/s = (vf - 25 m/s) / 4 s
-40 m/s = vf - 25 m/s
-15 m/s = vf
vAve = ( 25 m/2 + -15 m/s) / 2
vAve = 5 m/s
5 m/s = `ds / 4 s
20 m = `ds
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• How high will it be at the end of the sixth second?
answer/question/discussion: ->->->->->->->->->->->-> :
# -10 m/s/s = (vf - 25 m/s) / 6 s
-60 m/s = vf - 25 m/s
-35 m/s = vf
# vAve = ( 25 m/s + -35 m/s ) / 2
vAve = -5 m/s
# -5 m/s = `ds / 6 s
- 30 m = `ds
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15 minutes
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&#Very good responses. Let me know if you have questions. &#