#$&*
Your 'ball down ramp' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
#$&* Your general comment **
#$&* Will a steeper ramp give greater or lesser time? **
Copy this document into a word processor or text editor.
Follow the instructions, fill in your data and the results of your analysis in the given format.
Any answer you given should be accompanied by a concise explanation of how it was obtained.
To avoid losing your work, regularly save your document to your computer.
When you have completed your work:
Copy the document into a text editor (e.g., Notepad; but NOT into a word processor or html editor, e.g., NOT into Word or FrontPage).
Highlight the contents of the text editor, and copy and paste those contents into the indicated box at the end of this form.
Click the Submit button and save your form confirmation.
A ball is timed as it rolls from rest to the end of a ramp. The slope of the ramp is varied. Preliminary conclusions are drawn about the motion and the effect of ramp slope. A subsequent lab exercise uses the data from this lab to reach additional conclusions.
Most students report completion times between 45 minutes and 75 minutes hour, with a few reporting times as short as 25 minutes or as long as 2 hours. Median time of completion is around 1 hour.
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 interval on the steepest ramp will be the shortest, because the ball will accelerate faster.
#$&*
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 expect them to increase the greater the slope the greater the acceleration which would mean a higher velocity and a shorter time interval.
#$&*
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):
Right side
1 317.8281 319.7305 1.9024
2 337.418 339.2734 1.8554
3 349.3242 350.9883 1.6641
4 364.9648 366.7656 1.8008
5 382.8008 384.3633 1.5625
Left side
1 790.8008 792.7578 1.957
2 808.4531 810.3086 1.8555
3 825.4648 827.2539 1.7891
4 839.6055 841.457 1.8515
5 854.5938 856.2188 1.625
First column represents the starting (release) point of the marble. Second column represents the point at which the marble strikes the bracket. Third column represents the time interval between the two points.
#$&*
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):
Right side
1 1271.098 1272.211 1.113
2 1298.77 1299.895 1.18
3 1314.41 1315.535 1.125
4 1326.418 1327.387 .969
5 1336.066 1337.215 1.149
Left side
6 1967.805 1968.82 1.015
7 1980.883 1982.098 1.215
8 1991.09 1992.082 .992
9 2000.176 2001.336 1.16
10 2010.566 2011.738 1.173
#$&*
Repeat the preceding using 3 dominoes instead of 2. Enter your 10 time intervals using the same format as before.
Your answer (start in the next line):
Right side
1 2611.34 2612.398 1.058
2 2652.699 2653.449 .75
3 2664.641 2665.594 .953
4 2676.242 2677.266 1.024
5 2689.195 2690.285 1.09
Left side
1 2329.402 2330.336 .934
2 2338.656 2339.535 .879
3 2347.691 2348.574 .883
4 2356.863 2357.75 .887
5 2365.5 2366.309 .809
#$&*
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 3020.723 3021.809 1.085938
2 3032.051 3033.105 1.054688
3 3052.289 3053.223 .9335938
4 3059.648 3060.836 1.1875
5 3066.254 3067.066 .8125
#$&*
Repeat the preceding one last time, still using the 3 domino setup, but remove the disk and replace it with a piece of paper. You need time only 5 intervals, but if you prefer you may use 10. Enter your 5 (or 10) time intervals using the same format as before.
Your answer (start in the next line):
1 3436.5 3437.543 1.042969
2 3443.18 3444.148 .96875
3 3451.211 3452.309 1.097656
4 3458.629 3459.594 .9648438
5 3465.176 3466.254 1.078125
#$&*
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):
They support my hypotheses. The greater the slope the shorter the time.
#$&*
How do you think the average velocity of the ball is related to the slope of the ramp? Explain in as much detail as possible.
Your answer (start in the next line):
the greater the slope the faster the acceleration rate the greater or faster the velocity can be obtained in a shorter time interval
#$&*
Speculate on what it is that causes the average velocity on these ramps to change with slope.
Your answer (start in the next line):
The higher the slope the more gravity you have pushing the ball down the ramp and less gravity pushing the ball onto the ramp.
#$&*
How might you verify whether your speculations are indeed valid explanations?
Your answer (start in the next line):
Continue to raise the slope higher and higher and see if the time shortens more and more.
#$&*
Do your data conclusively show that the disk made a difference?
Your answer (start in the next line):
Yes it seemed to have slowed the ball down some which cause a slightly longer average time interval
#$&*
Do your data conclusively show that the piece of paper made a difference?
Your answer (start in the next line):
No.
#$&*
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):
#$&*
Had you placed the disk below the 'low' end of the ramp in a 1-domino setup, do you think the difference in times would have been greater or less? Do you think you would be better able distinguish the presence of a thinner object using the 1-domino setup, or the 3-domino setup? Explain your reasoning below:
Your answer (start in the next line):
I think that in the 1-domino set up the time difference would have been greater with the disk. I think that I would have been better able to distinguish the presence of a thinner object using the 1-domino setup over the 3. The 1 setup provides a slower roll with a lower slope so it would be easier to time the difference as appose to the 3 setup which rolls so fast it would be hard to time.
#$&*
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):
The balls velocity changes more quickly with the 3 domino setup. This is what allows it to hit in a shorter time interval. If the velocity did not change faster in the 3 than the 1 then the time intervals would not be faster in the 3 than the 1
#$&*
Your instructor is trying to gauge the typical time spent by students on these experiments. Please answer the following question as accurately as you can, understanding that your answer will be used only for the stated purpose and has no bearing on your grades:
Approximately how long did it take you to complete this experiment?
Your answer (start in the next line):
#$&*
*#&!
&#Your work on this lab exercise looks very good. Let me know if you have any questions. &#
Devise a procedure to test with the ammeter whether the total current through the generator is equal to the sum of the two currents through the bulbs, using a steady cranking rate of 1 cycle per second.
Note that at this rate, it is possible that neither bulb will dissipate enough energy to light. This does not change the fact that current is flowing through the bulbs; they just aren't getting hot enough to emit electromagnetic radiation.
Your procedure should measure the total current through the generator as well as the currents through each of the two bulbs.
Conduct your test and describe your procedure and your results in the box below:
Your answer (start in the next line):
your test of whether generator current is sum of currents through bulbs, and results:
your brief discussion/description/explanation:
In doubt a bit here.
#$&*
*#&!*#&!
@& You are doing fine here. However some of your observations appear to have used the wrong scale on the meter, and some of your reported currents are also high (again I suspect you read the wrong scale).
See if you can make corrections according to my notes.
&#Please see my notes and, unless my notes indicate that revision is optional, submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes.
If my notes indicate that revision is optional, use your own judgement as to whether a revision will benefit you. &#
*@