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.
** **
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: ->->->->->->->->->->->-> :
vAve = 20 cm / 2s
vAve = 10 cm/s
10 cm/s = (vf + v0) /2
20 cm/s = vf + 0 cm/s
vf = 20 cm/s
aAve = `dv / `dt
aAve = 20 cm/s / 2s
aAve = 10 cm/s/s
#$&*
• If the time interval is in error so that it is 3% longer than the actual time interval, then what are the actual values of the final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve = 20 cm / 1.94s
vAve = 10.31 cm/s
10.31 cm/s = (vf + 0 cm/s) / 2
vf = 20.62 cm/s
aAve = 20.62 cm/s / 1.94s
aAve = 10.63 cm/s/s
#$&*
• What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
3% for final velocity – (20 cm/s) / (20.62 cm/s) = .9699
6% for acceleration – (10 cm/s) / (10.63 cm/s) = .94
#$&*
• If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
N/A
#$&*
• If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
The percent error for acceleration is twice that of final velocity. Acceleration twice has to use the revised number in its calculation, versus, final velocity’s one time.
#$&*
** **
15 minutes
** **
Very well done.