#$&*
Phy 121
Your 'ball down ramp' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
#$&* Your general comment **
1 3.074219 3.074219
2 4.789063 1.714844
3 7.535156 2.746094
4 9.203125 1.667969
5 12.40234 3.199219
6 14.19531 1.792969
7 16.51953 2.324219
8 18.1875 1.667969
9 20.85547 2.667969
10 22.65234 1.796875
11 25.58203 2.929688
12 26.51953 .9375
13 30.01563 3.496094
14 31.77734 1.761719
15 34.92969 3.152344
16 36.51953 1.589844
17 40.07422 3.554688
18 41.68359 1.609375
19 45.08203 3.398438
20 46.55078 1.46875
21 53.19531 6.644531
22 54.69531 1.500
23 545.3008 490.6055
24 546.625 1.324219
25 551.0391 4.414063
26 552.2266 1.1875
27 555.25 3.023438
28 556.7344 1.484375
29 559.543 2.808594
30 560.9453 1.402344
31 565.2344 4.289063
32 566.3125 1.078125
33 598.5742 32.26172
34 599.8047 1.230469
35 602.5664 2.761719
36 603.5195 .953125
37 877.9258 274.4063
38 879.0313 1.105469
39 881.5586 2.527344
40 882.6523 1.09375
41 885.3359 2.683594
42 886.3477 1.011719
43 983.0703 96.72266
44 983.9883 .9179688
45 986.5625 2.574219
46 987.4063 .84375
47 989.6992 2.292969
48 990.5898 .890625
49 992.957 2.367188
50 994.0352 1.078125
51 998.0586 4.023438
52 998.8711 .8125
53 1002.66 3.789063
54 1003.816 1.15625
55 1005.984 2.167969
56 1007.031 1.046875
57 1010.93 3.898438
58 1011.82 .890625
59 1086.762 74.94141
60 1087.793 1.03125
61 1089.961 2.167969
62 1090.91 .9492188
63 1323.664 232.7539
64 1325.113 1.449219
65 1327.395 2.28125
66 1328.703 1.308594
67 1330.777 2.074219
68 1332.059 1.28125
69 1334.758 2.699219
70 1336.02 1.261719
71 1340.355 4.335938
72 1341.543 1.1875
73 1344.18 2.636719
74 1345.301 1.121094
75 1498.977 153.6758
76 1500.117 1.140625
77 1502.488 2.371094
78 1503.641 1.152344
79 1505.574 1.933594
80 1506.668 1.09375
81 1509.18 2.511719
82 1510.316 1.136719
83 1512.848 2.53125
84 1513.828 .9804688
#$&* Will a steeper ramp give greater or lesser time? **
Timing Ball down Ramp
The picture below shows a ball near the end of a grooved steel track (this steel track is a piece of 'shelf standard'); the shelf standard is supported by a stack of two dominoes. Your lab materials package contains two pieces of shelf standard; the shelf standard shown in the figure is white, but the one in your kit might be colored black, gold, silver or any of a variety of other colors.
If a ball rolls from an initial state of rest down three ramps with different slopes, the same distance along the ramp each time, do you think the time required to roll the length of the ramp will be greatest or least for the steepest ramp, or will the interval on the steepest ramp be neither the greatest nor the least? Explain why you think you have correctly predicted the behavior of the system.
Your answer (start in the next line):
I think the greatest time will be for the steepest ramp and the slowest time will be for the lowest ramp. If it is steep than the speed gets faster as the distance elapses rather than if it’s not steep it takes extra time to get to the bottom because the pull of gravity is not as strong.
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If we write down the slopes from least to greatest, next to the time intervals observed for those slopes, would you expect the time intervals to be increasing or decreasing, or do you think there would be no clear pattern? Explain why you think you have correctly described the behavior of the numbers in the table.
Your answer (start in the next line):
I would suspect the time intervals to be increasing because the slope is increasing and causing the speed to be much faster than the ramp with the least slope.
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Set up the shelf standard ramp on a reasonably level table, using a piece of 30-cm shelf standard and a single domino under the high end of the ramp. Position the dominoes so that the last .5 cm of the ramp extends beyond the point where the ramp contacts the domino,.and do the same in all subsequent setups.
Set the bracket on the table, touching the lower end of the ramp so that a ball rolling down the ramp will strike the bracket..
Mark a point about 3 cm below the top end of the ramp. Place a domino on the ramp to its high end is at this point, and place the ball just above the domino, so the domino is holding it back. Quickly pull the domino away from the ball so the ball begins to roll freely down the ramp. Allow the ball to roll until it strikes the bracket.
The bracket will probably move a little bit. Reset it at the end of the ramp.
Determine how far the ball rolled from release until it struck the bracket.
Now repeat, but this time use the TIMER. The first click will occur at the instant you release the ball, the second at the instant the ball strikes the bracket. Practice until you are as sure as you can be that you are clicking and pulling back the domino at the same instant, and that your second click is simultaneous with the ball striking the bracket.
When you are ready, do 5 trials 'for real' and record your time intervals.
Then reverse the system--without otherwise changing the position of the ramp, place the domino under the left end and position the bracket at the right end.
Time 5 trials with the ramp in this position.
In the space below, give the time interval for each trial, rounded to the nearest .001 second. Give 1 trial on each line, so that you will have a total of 10 lines, the first 5 lines for the first system, then 5 lines for the second system.
Beginning in 11th line give a short narrative description of what your data means and how it was collected.
Also describe what you were thinking, relevant to physics and the experiment, during the process of setting up the system and performing the trials.
Your answer (start in the next line):
1.715
1.668
1.793
1.668
1.797
1.762
1.590
1.609
1.469
1.500
I put the track up and every time I picked up the domino I clicked the timer button and again when the ball would strike the track at the end. The numbers above are the times it took for the ball to reach the bottom. I was thinking it should hit around the same time each trial.
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Now place two dominoes under the right end and repeat the process, obtaining the time interval for each of 5 trials.
Then place the two dominoes under the left end and repeat once more.
Enter your 10 time intervals using the same format as before.
Your answer (start in the next line):
1.324
1.188
1.484
1.402
1.078
1.230
1.105
1.094
1.012
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Repeat the preceding using 3 dominoes instead of 2. Enter your 10 time intervals using the same format as before.
Your answer (start in the next line):
.918
.844
.891
1.078
.813
1.156
1.047
.891
1.031
.949
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Repeat the preceding again, still using the 3 domino setup, but this time place a CD or a DVD disk (or something of roughly similar thickness) on the 'low' end of the ramp. You need time only 5 intervals, but if you prefer you may use 10. Enter your 5 (or 10) time intervals using the same format as before.
Your answer (start in the next line):
1.449
1.309
1.281
1.262
1.188
1.121
#$&*
Repeat the preceding one last time, still using the 3 domino setup, but remove the disk and replace it with a piece of paper. You need time only 5 intervals, but if you prefer you may use 10. Enter your 5 (or 10) time intervals using the same format as before.
Your answer (start in the next line):
1.141
1.152
1.094
1.137
.980
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Do your results support or fail to support the hypotheses you stated in the first two questions, regarding the relationship between time intervals and slopes? Explain.
Your answer (start in the next line):
Yes they do the steeper the ramp the fast the ball rolled.
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How do you think the average velocity of the ball is related to the slope of the ramp? Explain in as much detail as possible.
Your answer (start in the next line):
The average velocity is related to the slope of the ramp by the as the slope increased the velocity increased and as the slope decreased the velocity decreased.
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Speculate on what it is that causes the average velocity on these ramps to change with slope.
Your answer (start in the next line):
I think the slope causes the average velocity to change because it depends on how fast the ball rolls down the ramp.
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How might you verify whether your speculations are indeed valid explanations?
Your answer (start in the next line):
By using equations and figuring out the average velocity with each slope.
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Do your data conclusively show that the disk made a difference?
Your answer (start in the next line):
It made a little bit of a difference because it changed the slope.
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Do your data conclusively show that the piece of paper made a difference?
Your answer (start in the next line):
I don’t think the piece of paper change the results because it didn’t really change the slope any.
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Imagine that someone is placing different objects below the 'low' end of the ramp, and you are timing the ball. Assume that somehow the object placed below the 'low' end is hidden from you in a way that does not interfere with the timing process. Compared to the thickness of the DVD, how thin would the object have to be before you would be unable, using the TIMER, to observe a difference in times down the ramp?
Answer this question in the first line below. Express your answer in multiples or fractions of the thickness of a disk.
Starting in the second line, explain how you came to your conclusion, based on the results you obtained in this experiment. Also discuss how you could modify or refine the experiment, still using the TIMER, to distinguish the effect of the thinnest possible object placed under the 'low end.
Your answer (start in the next line):
I think if it was thin like a piece of paper you would not be able to recognize any difference. So if it was less than .5cm you would not be able to see any difference.
I came to my decision because when you used a piece of paper nothing really changed. You can change this experiment by changing the slope of the ramp more frequently. You could use different things on the low end to determine the thickness that you can see a change in.
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Had you placed the disk below the 'low' end of the ramp in a 1-domino setup, do you think the difference in times would have been greater or less? Do you think you would be better able distinguish the presence of a thinner object using the 1-domino setup, or the 3-domino setup? Explain your reasoning below:
Your answer (start in the next line):
I think the difference in times would probably be a greater time because it lowers the slope of the ramp. Yes I think you would have to use something thinner than the 1-domino setup. If you use something thinner in the 3-domino setup it would make the ramp steeper so it would change the results.
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Does the ball's velocity change more or less quickly with the 3-domino setup or the 1-domino setup? Explain as best you can how you could use your results to support your answer.
Your answer (start in the next line):
It changes more quickly with the 3-domino setup because the slope of the ramp is steepest.
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Your instructor is trying to gauge the typical time spent by students on these experiments. Please answer the following question as accurately as you can, understanding that your answer will be used only for the stated purpose and has no bearing on your grades:
• Approximately how long did it take you to complete this experiment?
Your answer (start in the next line):
40min.
#$&*
*#&!
&#Very good data and responses. Let me know if you have questions. &#