Phy231
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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Seed 8.1
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: ->->->->->->->->->->->-> :
v0=25m/s a=-9.8m/s^2 'dt=1s
'dt=(vf-v0)/a 1=(vf-25m/s)/-9.8 -9.8=(vf-25) vf=15.2m/s
#$&*
What will be its velocity at the end of two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
v0=25m/s a=-9.8m/s^2 'dt=2s 'dt=(vf-v0)/a 2=(vf-25m/s)/-9.8m/s^2 -19.6m/s=(vf-25m/s) vf=5.4m/s
#$&*
During the first two seconds, what therefore is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve=(25m/s+5.4m/s)/s=15.2m/s
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How far does it therefore rise in the first two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
'ds=15.2m/s*2s=30.4m
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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: ->->->->->->->->->->->-> :
3s=(vf-25m/s)/-9.8m/s^2 -29.4=(vf-25m/s) vf=-4.4m/s
4s=(vf-25m/s)/-9.8m/s^2 -39.2=vf-25m/s vf=-14.2m/s
#$&*
At what instant does the ball reach its maximum height, and how high has it risen by that instant?
answer/question/discussion: ->->->->->->->->->->->-> :
vo=25m/s vf=0m/s a=-9.8m/s^2 'dt=(0m/s-25m/s)/-9.8m/s^2 'dt=2.55s 'ds=(vf+v0)/2*'dt =25m/s/2*2/55s=31.875m
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What is its average velocity for the first four seconds, and how high is it at the end of the fourth second?
answer/question/discussion: ->->->->->->->->->->->-> :
v0=25m/s vf=-14.2m/s 'dt=4s vAve=(25m/s-14.2m/s)/2=5.4m/s 'ds=(-14.2m/s+25m/s)/2*.4s=21.6m
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How high will it be at the end of the sixth second?
answer/question/discussion: ->->->->->->->->->->->-> :
6s=(vf-25m/s)/-9.8m/s^2 -58.8m/s=(vf-25m/s) vf=-33.8m/s 'ds=(-33.8m/s+25m/s)/2*6s=-26.4m This should be positive because displacement should always be
positive.
#$&*
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40min
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3/8/10 12pm
Well done.