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? **
2.45 cm, 8 degrees clockwise
The first number is how far the block traveled after release. The second number is how far the block rotated after release.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of two dominoes: **
2.25 cm, 15 degrees clockwise
2.8 cm, 8 degrees clockwise
3.15 cm, 4 degrees clockwise
3.0 cm, 8 degrees counterclockwise
3.4 cm, 2 degrees counterclockwise
The first number in each line is the distance the block moved after release. The second number is the angle and direction of rotation after release.
** #$&* Rubber band lengths resulting in 5 cm, 10 cm and 15 cm slides: **
8.4 cm, 9.4 cm, not possible
The 15 cm slide is no possible within the 30% restriction.
The first two numbers are the length the rubber band needs to be stretched to achieve a block slide of 5 cm and 10 cm respectively.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of four dominoes: **
5.8 cm, 6 degrees counterclockwise
5.15 cm, 4 degrees clockwise
4.9 cm, 6 degrees counterclockwise
5.25 cm, 3 degrees clockwise
6.7 cm, 24 degrees clockwise
The first number of each line is the length the block moved with a tension equal to the weight of 4 dominoes. The second number on each line is how it rotated, and in what direction.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of six dominoes: **
11.55 cm, 9 degrees clockwise
11.1 cm, 3 degrees clockwise
14.2 cm, 13 degrees clockwise
11.9 cm, 27 degrees clockwise
11.9 cm, 30 degrees clockwise
The first number on each line is the length the block moved with a tension equal to the weight of 6 dominoes. The second number on each line is how it rotated, and in what direction.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of eight dominoes: **
This trail is not possible within the 30% restriction.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of ten dominoes: **
This trail is not possible within the 30% restriction.
** #$&* Rubber band length, the number of dominoes supported at this length, the mean and the standard deviation of the sliding distance in cm, and the energy associated with the stretch, for each set of 5 trials: **
8.1 cm, 2, 2.92, .4339, 1.11 N cm
8.7 cm, 4, 5.56, .7171, 4.23 N cm
9.3 cm, 6, 12.13, 1.203, 13.83 N cm
Not possible to complete
Not possible to complete
The units of energy reported here are Newton * cm, found by multiplying the number of dominoes by .19 N (the approximate force of each domino), and then by the mean distance moved.
You've correctly calculated the force due to each given length.
However you haven't correctly calculated the energy, which is based on the product of average rubber band force and the distance through which it acted. For example between the 8.7 cm and 9.3 cm length the force increased from about .8 N to about 1.2 N, and average of about 1.0 N. This average force occurs during the .6 cm displacement from one length to the other, so the work is 1.0 N * .6 cm = .6 N * cm.
It appears that you might have multiplied the force of the rubber band by the sliding distance; however the rubber band did not exert any force during most of the slide. Rubber band force occurred only while the rubber band was in contact with the block.
** #$&* 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: **
1.33, -2.655
Newton, Newtons * cm
The data points are very close to the line. Since only three points were possible, a curve in not indicated.
** #$&* Lengths of first and second rubber band for (first-band) tensions supporting 2, 4, 6, 8 and 10 dominoes: **
4, -16
Newton, Newton * cm
All data points are touching the line of best-fit in some capacity.
Since there are only 3 points, no curvature is indicated.
** #$&* Mean sliding distance and std dev for each set of 5 trials, using 2 rubber bands in series: **
8.1 cm, 6.6 cm
8.7 cm, 6.9 cm
9.3 cm, 7.0 cm
Not possible within 30% restriction.
Not possible within 30% restriction.
** #$&* Slope and vertical intercept of straight-line approximation to sliding distance vs. energy, units of slope and vertical intercept, description of the graph and closeness to line, any indication of curvature: **
5.01 cm, .4436 cm
6.86 cm, .8926 cm
10.75 cm, 1.017 cm
Not possible within 30% restriction.
Not possible within 30% restriction.
** 1-band sliding distance and 2-band sliding distance for each tension: **
8.1 cm, 5.01 cm
8.7 cm, 6.86 cm
9.3 cm, 10.75 cm
Not possible within 30% restriction.
Not possible within 30% restriction.
** #$&* 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: **
5.26, -38.39
cm/cm, cm
The data points are very closely scattered around the line. Since there are only 3 points, no curvature is indicated.
** #$&* Discussion of two hypotheses: 1. The sliding distance is directly proportional to the amount of energy required to stretch the rubber band. 2. If two rubber bands are used the sliding distance is determined by the total amount of energy required to stretch them. **
Sinc e the sliding distances were are times shorter with 2 rubber bands present, I would say the hypothesis is false.
** #$&* How long did it take you to complete this experiment? **
2 hours 10 minutes
** #$&* Optional additional comments and/or questions: **
You had an error in calculating the energy associated with the rubber band. I believe you can correct this fairly easily.
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