Phy 201
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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 take 20cm and divide by 2s to get the vAve=10cm/s. Since it is uniform acceleration from rest then vf is going to be
double the vAve which is vf=20cm/s.Now we know v0 and vf we get the `dv=20cm/s. We divide `dv by `dt which is 2s.
20cm/s/2s=10cm/s^2. vAve=10cm/s,vf=20cm/s,a=10cm/s^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:
Time is 2s with 3%error would be 2s*.03=.06s.we subtract this from 2s we get 1.94s. We divide this into `ds=20cm we get
10.31cm/s and vf would be double at 20.62cm/s.This would also be the `dv so `dv/`dt=a. 20.62cm/s/1.94s=10.63cm/s^2
What is the percent error in each?
answer/question/discussion:
We take the 2s interval vf is 20cm/s and divide that by the 1.94s interval vf 20.62cm/s we get .97. we have an uncertainty 0f
+-.01. we take .01/.97= 1% error
We take the 2s interval a is 10cm/s^2 and divide that by the 1.94s interval a 10.63cm/s^2 we get .94 . we have an uncertainty
of +-.01. we take .01/.94= 1% error
If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion:
The percent errors are the same. I believe this so because your using the same time interval.The numbers are still calculated
the same way by the 3% time error
If the percent errors are different explain why it must be so.
answer/question/discussion:
n/a
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30 minutes
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&#This looks very good. Let me know if you have any questions. &#