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Phy 201
Your 'energy conversion 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.
#$&* Your optional message or comment: **
#$&* How far and through what angle did the block displace on a single trial, with rubber band tension equal to the weight of two dominoes? **
You will make a similar mark for the final position for each trial of the experiment, and from these marks you will later be able to tell where the center mark ended up for each trial, and the approximate orientation of the block at the end of each trial.
• Based on this first mark, how far, in cm, did the block travel after being released, and through approximately how many degrees did it rotate before coming to rest?
• If the block didn't move, your answers to both of these questions will be 0.
Answer in comma-delimited format in the first line below. Give a brief explanation of the meaning of your numbers starting in the second line.
Your answer (start in the next line):
2.32, 0
2.32 is the amount of cm the block traveled after the rubber band was stretched to a length of 7.49 cm and then released. 0 is the degrees of rotation the block rotated before coming to rest.
#$&* _ 2 rb tension how far and thru what angle
Tape the paper to the tabletop, or otherwise ensure that it doesn't move during subsequent trials.
• Repeat the previous instruction until you have completed five trials with the rubber band at same length as before.
Report your results in the same format as before, in 5 lines. Starting in the sixth line give a brief description of the meaning of your numbers and how they were obtained:
Your answer (start in the next line):
2.32, 0
2.35, 0
2.75, 0
2.60, 0
2.65, 0
The first column is in cm and represents the distance traveled after the rubber band was stretched to a length of 7.49 cm and released. The second column is the degrees of rotation experienced by the block, of which I didn't observe any.
#$&* _ trials on paper
Now, without making any marks, pull back a bit further and release.
• Make sure the length of the rubber band doesn't exceed its original length by more than 30%, with within that restriction what rubber band length will cause the block to slide a total of 5 cm, then 10 cm, then 15 cm.
• You don't need to measure anything with great precision, and you don't need to record more than one trial for each sliding distance, but for the trials you record:
• The block should rotate as little as possible, through no more than about 30 degrees of total rotation, and
• it should slide the whole distance, without skipping or bouncing along.
• You can adjust the position of the rubber band that holds the block together, the angle at which you hold the 'tail', etc., to eliminate skipping and bouncing, and keep rotation to a minimum.
Indicate in the first comma-delimited line the rubber band lengths that resulted in 5 cm, 10 cm and 15 cm slides. If some of these distances were not possible within the 30% restriction on the stretch of the rubber band, indicate this in the second line. Starting in the third line give a brief description of the meaning of these numbers.
Your answer (start in the next line):
7.8, 8.5, 9.2
All were possible within 30%
These numbers are the lengths of the rubber band stretched necessary in order to get the block to slide 5, 10, and 15 cm, respectively.
#$&* _ rb lengths for 5, 10, 15 cm slides
Now record 5 trials, but this time with the rubber band tension equal to that observed (in the preceding experiment) when supporting 4 dominoes. Mark and report only trials in which the block rotated through less than 30 degrees, and in which the block remained in sliding contact with the paper throughout.
Report your distance and rotation in the same format as before, in 5 lines. Briefly describe what your results mean, starting in the sixth line:
Your answer (start in the next line):
4.49, 0
4.62, 0
5.28, 0
4.80, 0
5.24, 0
The first column is the length in cm traveled by the block when the rubber band was stretched to a length of 7.68 cm. The second column is the degrees rotated by the block in each trial.
#$&* _ 5 trials 4 domino length
Repeat with the rubber band tension equal to that observed when supporting 6 dominoes and report in the same format below, with a brief description starting in the sixth line:
Your answer (start in the next line):
8.75, 0
9.20, 0
9.55, 0
9.36, 0
8.95, 0
The first column is the length in cm traveled by the block when the rubber band was stretched to a length of 7.82 cm. The second column is the degrees rotated by the block in each trial.
#$&* _ 5 trials for 6 domino length
Repeat with the rubber band tension equal to that observed when supporting 8 dominoes and report in the same format below, including a brief description starting in the sixth line:
Your answer (start in the next line):
12.62, 0
13.05, 0
12.63, 0
12.75, 0
13.20, 0
The first column is the length in cm traveled by the block when the rubber band was stretched to a length of 8.01 cm. The second column is the degrees rotated by the block in each trial.
#$&* _ 5 trials for 8 domino length
Repeat with the rubber band tension equal to that observed when supporting 10 dominoes and report in the same format below, including your brief description as before:
Your answer (start in the next line):
14.55, 0
14.70, 0
15.18, 0
15.15, 0
14.95, 0
The first column is the length in cm traveled by the block when the rubber band was stretched to a length of 8.19 cm. The second column is the degrees rotated by the block in each trial.
#$&* _ 5 trials for 10 domino length
In the preceding experiment you calculated the energy associated with each of the stretches used in this experiment.
The question we wish to answer here is how that energy is related to the resulting sliding distance.
• For each set of 5 trials, find the mean and standard deviation of the 5 distances. You may use the data analysis program or any other means you might prefer.
• In the space below, report in five comma-delimited lines, one for each set of trials, the length of the rubber band, the number of dominoes supported at this length, the mean and the standard deviation of the sliding distance in cm, and the energy associated with the stretch.
• You might choose to report energy here in Joules, in ergs, in Newton * cm or in Newton * mm. Any of these choices is acceptable.
• Starting in the sixth line specify the units of your reported energy and a brief description of how your results were obtained. Include your detailed calculations and specific explanation for the third interval. Be sure to give a good description of how you obtained the energy associated with each stretch:
Your answer (start in the next line):
7.49, 2, 2.534, .1898, 0.00551
7.68, 4, 4.886, 0.3589, 0.0804
7.82, 6, 9.162, 0.3185, 0.0840
8.01, 8, 12.85, 0.2616, 0.0866
8.19, 10, 14.91, 0.2765, 0.0896
The first column is cm the rubber band is stretched. The second column is the number of dominoes held at that length. The third column is cm, representing the mean sliding distance after 5 trials at the respective rubber band length. The fourth column is the average deviation from the mean. The fifth column is the energy associated with this length of stretch.
#$&* _ for each set of trials length, # dom, mean, std of sliding dist, energy _ describe how results obtained esp energy calculations
Sketch a graph of sliding distance vs. energy, as reported in the preceding space .
• Fit the best possible straight line to your graph, and give in the first comma-delimited line the slope and vertical intercept of your line.
• In the second line specify the units of the slope and the vertical intercept.
• Starting in the third line describe how closely your data points cluster about the line, and whether the data points seem to indicate a straight-line relationship or whether they appear to indicate some sort of curvature.
• If curvature is indicated, describe whether the curvature appears to indicate upward concavity (for this increasing graph, increasing at an increasing rate) or downward concavity (for this increasing graph, increasing at a decreasing rate).
Your answer (start in the next line):
8.57 * 10^-4, 0.0780
The slope is J / cm, the vertical intercept is J.
2 of the data points are above the line, 2 are below, but all are very close to the line. The points definitely indicate a straight-line relationship.
The final point seems to go up slightly more positively than the rest, possibly indicating a curvature but mostly it really looks very straight. If I were to continue on with larger slider distances, and a curvature did form, it seems to me that it would trend towards being upward concavity, if anything.
#$&* _ sliding dist vs. energy slope, vert intercept of st line, how close to line, describe curvature if any
Now repeat the entire procedure and analysis, but add a second rubber band to the system, in series with the first.
• For each trial, stretch until the first rubber band is at the length corresponding to the specified number of dominoes, then measure the second rubber band and record this length with your results.
• When graphing mean sliding distance vs. energy, assume for now that the second rubber band contributes an amount of energy equal to that of the first. You will therefore use double the energy you did previously.
• When you have completed the entire procedure report your results in the space es below, as indicated:
Report in comma-delimited format the length of the first rubber band when supporting the specified number of dominoes, and the length you measured in this experiment for second band. You will have a pair of lengths corresponding to two dominoes, four dominoes, ..., ten dominoes. Report in 5 lines:
Your answer (start in the next line):
7.49, 7.35
7.68, 7.49
7.82, 7.52
8.01, 7.74
8.19, 7.95
#$&* _ lengths of 1st and 2d rbs in series each of 5 trials
Report for each set of 5 trials your mean sliding distance and the corresponding standard deviation; you did five sets of 5 trials so you will report five lines of data, with two numbers in each line:
Your answer (start in the next line):
3.522, 2612
6.304, .1615
7.172, .2815
9.13, .2072
13.17, .2626
#$&* _ sliding dist and std dev each tension
Give the information from your graph:
• Give in the first comma-delimited line the slope and vertical intercept of your line.
• In the second line specify the units of the slope and the vertical intercept.
• Starting in the third line describe how closely your data points cluster about the line, and whether the data points seem to indicate a straight-line relationship or whether they appear to indicate some sort of curvature.
• If curvature is indicated, describe whether the curvature appears to indicate upward concavity (for this increasing graph, increasing at an increasing rate) or downward concavity (for this increasing graph, increasing at a decreasing rate).
Your answer (start in the next line):
0.0033, 0.153
The slope is in J/cm. The vertical intercept is in J.
The data points are almost exactly along the line. The points seem to indicate a straight-line relationship.
#$&* _ slope, vert intercept, describe curvature
In the space below, report in the first line, in comma-delimited format, the sliding distance with 1 rubber band under 2-domino tension, then the sliding distance with 2 rubber bands under the same 2-domino tension.
Then in the subsequent lines report the same information for 4-, 6-, 8- and 10-domino tensions.
You will have five lines with two numbers in each line:
Your answer (start in the next line):
2.534, 3.522
4.886, 6.304
9.162, 7.172
12.85, 9.13
14.91, 13.17
#$&* _ 5 lines comparing 1 rb to 2 rb trials
Your preceding answers constitute a table of 2-rubber-band sliding distances vs. 1-rubber-band sliding distances.
Sketch a graph of this information, fit a straight line and determine its y-intercept, its slope, and other characteristics as specified:
• Give in the first comma-delimited line the slope and vertical intercept of your line.
• In the second line specify the units of the slope and the vertical intercept.
• Starting in the third line describe how closely your data points cluster about the line, and whether the data points seem to indicate a straight-line relationship or whether they appear to indicate some sort of curvature.
• If curvature is indicated, describe whether the curvature appears to indicate upward concavity (for this increasing graph, increasing at an increasing rate) or downward concavity (for this increasing graph, increasing at a decreasing rate).
Your answer (start in the next line):
0.7059, 2.5
The slope and vertical intercept are in cm.
The points are evenly distributed along the line, 2 above and 3 below but all very close and evenly close to the line. The points indicate a straight-line relationship.
#$&* _ graph 2 rb dist vs 1 rb dist _ slope and intercept _ describe any curvature
To what extent do you believe this experiment supports the following hypotheses:
The sliding distance is directly proportional to the amount of energy required to stretch the rubber band. If two rubber bands are used the sliding distance is determined by the total amount of energy required to stretch them.
Your answer (start in the next line):
I thought with two rubber bands there would be double the energy and therefore twice as much distance, but this didn't seem to be the case. This can be due to human error in my own experiment, but no, within my collected data this experiment didn't support that hypothesis. With 1 rubber band my data does support that the more energy, the farther the sliding distance. When 2 rubber bands were involved, the energy was allegedly doubled but the distance was not doubled.
#$&* _to what extend is hypothesis of sliding dist prop stretching energy supported _ to what extent for 2 rb
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):
About 2.5 hours
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*#&!
&#Very good data and responses. Let me know if you have questions. &#