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? **
2.8 cm, about 10 degrees
The first number is how far, in cm, the block traveled after being released and the second number is how many degrees the block rotated before coming to a rest.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of two dominoes: **
2.3 cm, about 15 degrees
1.6 cm, about 10 degrees
2.9 cm, about 20 degrees
3.3 cm, about 20 degrees
1.9 cm, about 10 degrees
I obtained these results by releasing the rubber band and seeing how many cm it traveled and about how many degrees it rotated before coming to a rest.
** Rubber band lengths resulting in 5 cm, 10 cm and 15 cm slides: **
7.7 cm, 8.2 cm, 8.9 cm
All of the distances were possible within the 30% restriction on the stretch of the rubber band.
These numbers are the lengths of the rubber band that resulted in 5 cm, 10 cm , and 15 cm slides of the block.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of four dominoes: **
3.5 cm, about 20 degrees
4.1 cm, about 25 degrees
3.8 cm, about 15 degrees
4.3 cm, about 15 degrees
3.9 cm, about 20 degrees
These results are how many centimeters the block slid with four dominoes. The second number is how many degrees the block rotated before coming to rest.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of six dominoes: **
5.9 cm, about 25 degrees
6.3 cm, about 30 degrees
5.2 cm, about 20 degrees
6.6 cm, about 25 degrees
5.4 cm, about 15 degrees
The first number is how many cm the block, containing 6 dominoes, slid after being released. The second number is how many degrees the block rotated before coming to a rest.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of eight dominoes: **
6.7 cm, about 20 degrees
6.9 cm, about 20 degrees
7.2 cm, about 15 degrees
6.5 cm, about 10 degrees
7.6 cm, about 20 degrees
The first number is how many cm the block, containing 8 dominoes, slide after being released. The second number is how many degrees the block rotated before coming to rest.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of ten dominoes: **
7.5 cm, about 30 degrees
7.9 cm, about 30 degrees
8.2 cm, about 20 degrees
7.8 cm, about 20 degrees
8.6 cm, about 30 degrees
The first number is how many cm the block, containing 10 blocks, slid after being released. The second number is how many degrees the block rotated before coming to rest.
** Rubber band length, 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, for each set of 5 trials: **
7.5 cm, 3 dominoes, 2.4 mean, .7 SD, 10.69 N*cm
7.8 cm, 4 dominoes, 3.92 mean, .30 SD, 11.55 N*cm
8.2 cm, 6 dominoes, 5.88 mean, .59 SD, 12.77 N*cm
8.6 cm, 8 dominoes, 6.98 mean, .43 SD, 14.05 N*cm
8.9 cm, 10 dominoes, 8.0 mean, .42 SD, 15.04 N*cm
I obtained the energy by multiplying the force exerted by the displacement.
*&$I suspect you multiplied the maximum force exerted by the rubber band by the total sliding distance of the block. However the rubber band did not exert its maximum force through this entire distance; in fact the maximum force was exerted only at the very first instant. After that the force exerted by the rubber band decreased, reaching 0 at the point where the rubber band went slack.
To get the work done by the rubber band you have to analyze the force vs. length graph, as done in the preceding lab.
As a point of reference, if the rubber band exerts a force of 2 N at its 9 cm length, decreasing to 0 N at a length of 7 cm, then it exerts and average force of about 1 N through a displacement of 2 cm and does work 1 N * 2 cm = 2 N * cm. This estimate can be modified using the techniques you obtained in the preceding experiment.*&$
** Slope and vertical intercept of straight-line approximation to sliding distance vs. energy, units of slope and vertical intercept, description of the graph and closeness to line, any indication of curvature: **
.34 slope, 8.41 vertical intercept
The slope has no units and the vertical intercept is in N
My data points cluster closely about the line and they indicate some sort of curvature.
The curvature appears to indicate an upward cancavity
** Lengths of first and second rubber band for (first-band) tensions supporting 2, 4, 6, 8 and 10 dominoes: **
.18 slope, 19.2 vertical intercept
no units for slope and Newtons for vertical intercept
There was curvature that was increasing at an increasing rate
** Mean sliding distance and std dev for each set of 5 trials, using 2 rubber bands in series: **
7.5 cm, 7.9 cm
7.8 cm, 8.0 cm
8.2 cm, 8.5 cm
8.6 cm, 8.9 cm
8.9 cm, 9.1 cm
** Slope and vertical intercept of straight-line approximation to sliding distance vs. energy, units of slope and vertical intercept, description of the graph and closeness to line, any indication of curvature: **
4.9 mean, .57 SD
5.8 mean, .63 SD
6.5 mean, .66 SD
6.9 mean, .58 SD
7.6 mean, .65 SD
** 1-band sliding distance and 2-band sliding distance for each tension: **
7.5 cm, 7.9 cm
8.3 cm, 8.7 cm
8.6 cm, 9.0 cm
9.1 cm, 9.2cm
9.3, 9.4 cm
** Slope and vertical intercept of straight-line approximation to 2-band sliding distance vs. 1-band sliding distance, units of slope and vertical intercept, description of the graph and closeness to line, any indication of curvature: **
.83 slope, 1.2 vertical intercept
they points cluster about the line
there is an increasing at an increasing rate curvature
** Discussion of two hypotheses: 1. The sliding distance is directly proportional to the amount of energy required to stretch the rubber band. 2. If two rubber bands are used the sliding distance is determined by the total amount of energy required to stretch them. **
I believe that the experiment does support the hypothesis because it does show that the sliding distance is directly proportional to the amount of energy require to stretch the rubber band.
** How long did it take you to complete this experiment? **
2 hours
** Optional additional comments and/or questions: **
Your energy estimates are not done correctly, though most of your other calculations appear good. Please see my note and revise accordingly.
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