Phy 121
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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: average velocity=0.2m/2s=0.1m/s, final velocity=.2m/s because it is double the average velocity when it is uniform and starts from rest, acceleration=0.2
• 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:0.206m/s and .206 for acceleration also
• What is the percent error in each?
answer/question/discussion:0.006
• If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion: because the acc. and velocity were the same so if you use the same percent error, you get the same answer
• If the percent errors are different explain why it must be so.
answer/question/discussion:
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20 minutes
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You've explained how you got your final velocity, which is correct, but not how you then calculated your acceleration, which is not correct.
Your calculation for the 3% increase in interval is incorrect. Among other things, if the interval is longer the calculated velocity and acceleration will be shorter; and .206 is 3% greater than .200, not .006% longer.
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