Phy 231
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: ->->->->->->->->->->->-> :
+ 25 m/s and -10 m/s^2
25 m/s + -10 m/s^2 * 1 sec = 15 m/s
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• What will be its velocity at the end of two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
25 m/s + -10m/s^2 * 2 sec = 5 m/s
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• During the first two seconds, what therefore is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
( 25 m/s + 5 m/s) / 2 = 15 m/s
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• How far does it therefore rise in the first two seconds?
answer/question/discussion: ->->->->->->->->->->->-> :
15 m/s * 2 sec = 30 meters.
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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: ->->->->->->->->->->->-> :
At 2 seconds, the velocity is 5 m/s. An additional second would be 5 m/s – 15 m/s which is -5 m/s. Another second would be -5 m/s – 10 m/s which is – 15 m/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 initially starts at 25 m/s and continues downward, therefore, the maximum height can be found by looking at the distance it took the ball to fall 25 m/s to rest which is 0 m/s. 25 m/s / 10 m/s = 2.5 seconds. 25 m/s + 0 m/s / 2 = 12.5 m/s which is the vAve. 12.5 m/s * 2.5 sec = 31.25 meters which will be the maximum height.
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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: ->->->->->->->->->->->-> :
The average velocity for the first four seconds is (25 m/s + -15 m/s) / 2 = 5 m/s. 5 m/s * 4 sec = 20 meters which is the height.
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• How high will it be at the end of the sixth second?
answer/question/discussion: ->->->->->->->->->->->-> :
-15 m/s is the velocity at 4 seconds,
-15 m/s + -10 m/s = -25 m/s is the velocity at 5 seconds,
- 25 m/s + - 10 m/s = -35 m/s is the velocity at 6 seconds.
(25 m/s + -35 m/s)/2 = -30 m/s is the average velocity at 6 seconds. Past the value of 0, the acceleration and therefore it is not possible to calculate a valid height for the ball at 6 seconds.
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30 minutes
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&#Very good work. Let me know if you have questions. &#