Phy 201
Your 'cq_1_09.1' 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 accelerates uniformly as it rolls 20 cm down a ramp, starting from rest, in 2 seconds.
• What are its average velocity, final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> : We know that our displacement divided by time gives us our average velocity. So this is 10cm/s. Since we started from rest we know that our final velocity is double our average velocity. So this is 20cm/s. Our acceleration is our change in velocity divided by time which is 20cm/s / 2s = 10cm/s^2.
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• If the time interval is in error so that it is 3% longer than the actual time interval, then what are the actual values of the final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> : If there is a 3% error then the actual time is 1.94 seconds. This will change our average velocity to 20cm/1.94s = 10.31cm/s. This makes my final velocity 20.62cm/s and the acceleration 10.63cm/s^2
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• What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
Velocity has a 3.05 percent error (20cm/s – 20.62cm/s)/20.62 = |.0305|
Acceleration has a 5.9 percent error (10cm/s^2 – 10.63cm/s^2)/10.63cm/s^2 = |.059|
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• If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
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• If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
They are different because when you have to calculate acceleration you have to use the newly found final velocity. So average velocity will only incorporate one changed figure (time) while acceleration will use two changed figures(final velocity , time)
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25 Minutes
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&#Very good responses. Let me know if you have questions. &#