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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.
** CQ_1_08.1_labelMessages **
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45
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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: ->->->->->->->->->->->-> :
vf=v0+a*'dt
vf=25m/s +(-10m/s^2)*(1s)
vf=15m/s
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What will be its velocity at the end of two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
vf=v0+a*'dt
vf=25m/s +(-10m/s^2)*(2s)
vf=5m/s
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During the first two seconds, what therefore is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve=(vf+v0)/2
vAve=(5m/s+25m/s)/2
vAve=15m/s
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How far does it therefore rise in the first two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve='ds/'dt
15m/s*2s='ds
30m='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: ->->->->->->->->->->->-> :
vf=v0+a*'dt
vf=25m/s +(-10m/s^2)*(3s)
vf=-5m/s
vf=v0+a*'dt
vf=25m/s +(-10m/s^2)*(4s)
vf=-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: ->->->->->->->->->->->-> :
a='dv/'dt
-10m/s^2=(0m/s-25m/s)/'dt
'dt=-25m/s/-10m/s^2
'dt=2.5s
'ds=(0m/s+25m/s)/2*'dt
'ds=25m/s/2*2.5s
'ds=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: ->->->->->->->->->->->-> :
vAve=(-15m/s+25m/s)/2
vAve=5m/s
5m/s='ds/'dt
'ds=5m/s*4s
'ds=20m
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How high will it be at the end of the sixth second?
answer/question/discussion: ->->->->->->->->->->->-> :
-10m/s^2=(vf-25m/s)/'6s
-60m/s=vf-25m/s
-60m/s+25m/s=vf
-35m/s=vf
vAve='ds/'dt
vAve=(vf+v0)/2
(vf+v0)/2='ds/'dt
((vf+v0)/2)*'dt='ds
((-35m/s+25m/s)/2)*6s='ds
-5m/s*6s='ds
-30m='ds
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