#$&*
course PHY 231
10/31 6:23 pm. I know I'm going to have to spend more time with this because all of it doesn't seem to work out like I think it should am not sure what's bothering me about it yet. The sound editor section seems to be the setup that more time with would yield the best results.
Acceleration vs. Ramp Slope****
I have a lot uncertainties about the results I have. I feel like I set everything up right but not all of the data is as consistent as it should be considering the precision we are trying to achieve.
Setup: I had the typical setup we've been using with the following modifications; one: I marked the ramp where it was lying on the edge of my domino and used that mark for each trial and setup. The track length was 29.3 cm and I varied the start position by about 1 mm so the ramp distance is 29.3± 0.1 and my domino lying flat was 0.8 cm thick and on edge was 2.5 cm. So my slopes were 0.027 and 0.0856 respectively. I'm not sure about the error in the domino measurements and measuring those dimensions more accurately would improve upon my results, especially in the sound edit portion.
#$&*
Pendulum:
****
My pendulum had a length of 12.2 cm and so a period of T= 0.6986 s. This is where I may have made a mistake but the pendulum seemed to sync up for both slopes at this length with more strikes for the second slope. s = 29.3±0.1 cm. I only have one time for both slopes for this setup because the strikes are so far apart that a mm of change in s made no recordable difference in strikes. I used a = 2x/t^2 to find a and the then error was x_err+ 2(t_err). t_err may be greater than what I have but it seems to work out about the same as when I used the TIMER program.
Data format:
slope 1
time
acceleration
slope 2
time
acceleration
∆a
∆slope
∆a/∆slope
#$&*
****
slope 1
1.75±0.1
19.07±0.12
slope 2
1.05±0.1
52.97±0.10
33.9±0.1
0.0586
578.5
#$&*
Projectile:
****
This setup seems to have more uncertainty than the pendulum since my landing positions had a fair amount of variance. I did a lot of trials and most are grouped close together but there were enough that were farther apart to skew my data some. For me this part has the least likely answers and they vary more from the other two than the other two vary from each other. I used ∆y= tan ø(∆x)-1/2at^2 to find t and then v0= t*cos ø and then from there I used a= (v^2/2s) where s is 29.3±0.1 cm I found ø using arctan(rise/run) and that resulted in 1.56º and 4.9º. The error seems greatest in the ∆x distances as my ∆y was 77.1 cm which is as close as my meter stick could measure and it seemed to be right on that so I didn't add variance there but I know there could be but not nearly as much as my ∆x's varied so it seemed relative to those that is was negligible even in these more precise calculations. My ∆x ranged from 10 to 10.4 cm with 90% in the 10.2 area and based on this I found the ∆x to be 10.2±0.07 for slope 1 and for slope a similar process produced ∆x= 19.88±0.05.
Data format:
slope 1
∆x
∆t
v0
a
slope 2
∆x
∆t
v0
a
∆a
∆a/∆slope
#$&*
****
slope 1
10.2±0.07
0.397±0.013
25.7±0.027
11.27±0.01
slope 2
19.88±0.05
0.4±0.008
49.88±0.01
42.46±0.02
30.79±0.02
533.25±0.02
#$&*
****
Sound Editor:
Setup: Here I used a USB headset with a microphone and Audacity. To minimize the speed of sound problem I place the mic exactly in the middle of the ramp so it was 6 in from either side and thus the sound coming in from either side took only 0.0005 seconds which is beyond the range of Audacity as we are using it. For the end sound I used a domino but it was the start sound that I had a problem with as I couldn't get the domino out from in front of the ball without moving it. It just didn't seem to work for me. What I did find was that I could tap the domino at the exact same time as I released the ball. I did not release the ball at the same time as I started to tap but at the very instant that I did tap. This wasn't too hard too coordinate but at this level of precision I did have some minor variances that seem to have much greater overall effect than it would seem they should. I had 3 good runs with each slope. I'm not sure about how to process these as since the variance was more significant than in the other setups. So I will report the data and conclusions for each of the three good runs. I may need to take more time to get more data here to even this out to be more consistent. My ∆a/∆slope is much higher here than in the all three of my other setups, the two here and the timer before and my error calculations here don't seem to be as consistent as above. I'll certainly have to spend a little more time on this to really get it right because I know it will be the most accurate setup when I know I'm doing it right.
Data format:
slope 1
t11, a11
t12, a12
t13, a13
slope 2
t21, a21
t22, a22
t23, a23
(ave)∆a
∆a/∆slope
#$&*
****
slope 1
1.659±0.001, 21.291±0.005
1.705±0.001, 20.158±0.005
1.642±0.001, 21.735±0.005
slope 2
0.957±0.001, 63.984±0.006
0.984±0.001, 60.521±0.006
0.924±0.001, 68.630±0.006
∆a_ave
43.111±0.011
735.688±0.0003"
I purposely haven't calculated what the results should be for this system, so I really don't know how well you did. However all of your results are completely plausible. After I get reports from most of the class, we'll see how it sorts out.
Your error bounds are way too low, but we'll discuss that in class Wednesday.
#$&*