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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: ->->->->->->->->->->->-> scussion:
a = vf-v0/`dt
vf = a`dt + v0
vf= -10m/s^2 * 1s + 25m/s
vf= -10m/s+25m/s
vf= 15m/s after 1s
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What will be its velocity at the end of two seconds?
answer/question/discussion: ->->->->->->->->->->->-> scussion:
vf = -10m/s^2 * 2s + 25m/s
vf = -20m/s + 25m/s
vf = 5m/s
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During the first two seconds, what therefore is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> scussion:
vAve= (v0+vf)/2
vAve= (25m/s+5m/s)/2=15m/s
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How far does it therefore rise in the first two seconds?
answer/question/discussion: ->->->->->->->->->->->-> scussion:
'ds= vAve*'dt
'ds= 15m/s* 2s
'ds= 30m
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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: ->->->->->->->->->->->-> scussion:
vf = -10m/s^2 * 3s + 25m/s
vf = -5m/s
vf = -10m/s^2 * 4s + 25m/s
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: ->->->->->->->->->->->-> scussion:
a=(vf-v0)/`dt
`dt = (vf-v0)/a
(0 m/s - 25m/s) / -10m/s^2
'dt = -25m/s / -10m/s^2
'dt= 2.5s
`ds = vAve*`dt
'ds = 25m/s / 2 *2.5s
'ds = 12.5m/s * 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: ->->->->->->->->->->->-> scussion:
vAve=(vf+v0)/2
vAve= (-15m/s + 25m/s)/2
vAve= 10m/s / 2
vAve= 5m/s
`ds = vAve`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: ->->->->->->->->->->->-> scussion:
-35m/s
vAve = (-35m/s + 25m/s) / 2
vAve = -10m/s / 2
vAve= -5m/s
'ds= -5m/s / 6s
'ds= -.83m
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*#&!
&#Very good work. Let me know if you have questions. &#