cq_1_051

Phy 201

Your 'cq_1_05.1' 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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The problem:

A ball accelerates at 8 cm/s^2 for 3 seconds, starting with velocity 12 cm/s.

• What will be its velocity after the 3 seconds has elapsed?

answer/question/discussion: ->->->->->->->->->->->-> :

(3 sec) * (8 cm/s^2) = 24 cm/s + 12 cm/s = 36 cm/s

#$&*

• Assuming that acceleration is constant, what will be its average velocity during this interval?

answer/question/discussion: ->->->->->->->->->->->-> :

vAve = (36 cm/s + 12 cm/s) / 2 = 24 cm/s

#$&*

• How far will it travel during this interval?

answer/question/discussion: ->->->->->->->->->->->-> :

20 cm + 28 cm + 36 cm = 84 cm

If the ball travels 84 cm in 3 seconds, then its average velocity is 28 cm/s.

This contradicts your average velocity of 24 cm/s.

You appear to have calculated the distance for each second, but based your calculation on the maximum velocity achieved during each of the three seconds, rather than on the average velocities.

You don't need to do a second-by-second calculation in this case.

#$&*

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5 minutes

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Solution

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