seed question 41

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course phy 231

June 30, 11:06

Copy the problem below into a text editor or word processor. •This form accepts only text so a text editor such as Notepad is fine.

• You might prefer for your own reasons to use a word processor (for example the formatting features might help you organize your answer and explanations), but note that formatting will be lost when you submit your work through the form.

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You should enter your answers using the text editor or word processor. You will then copy-and-paste it into the box below, and submit.

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The problem:

A ball is moving at 10 cm/s when clock time is 4 seconds, and at 40 cm/s when clock time is 9 seconds.

• Sketch a v vs. t graph and represent these two events by the points (4 sec, 10 cm/s) and (9 s, 40 cm/s).

answer/question/discussion (start in the next line):

The graph of v vs. t would have velocity on the y-axis and clock time on the x-axis. At 4 sec you would plot a value of 10 cm/s and at 9 sec a value of 40 m/s.

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• Sketch a straight line segment between these points.

answer/question/discussion (start in the next line):

After sketching a straight line segment between the points (9, 40) and (4, 10), the slope of the line would represent the acceleration of the ball which would be (40 m/s - 10 m/s)/(9 sec - 4 sec) = rise/run = (30 m/s)/(5 sec) = 6 m/s^2.

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• What are the rise, run and slope of this segment?

answer/question/discussion (start in the next line):

rise = (40 m/s - 10 m/s)

run = (9 sec - 4 sec)

slope = rise/run = 30 m/s/5 sec = 6 m/s^2

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• What is the area of the graph beneath this segment?

answer/question/discussion (start in the next line):

The area beneath the line is the distance the ball traveled with the given parameters. `ds = (40 m/s + 10 m/s)/2 * 5 sec = 125 meters. Or, area underneath = (10m/s * 5 sec) + .5 * 5 sec * 30m/sec = 50 meters + 75 meters = 125 meters.

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