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: **
I cannot find my calibrated rubber band #1 from last summer, so I'm using #2. I have done the calculations from last lab for this rubber band and will use them here. I can post that data if it's needed for a discussion.
** 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? **
1.6,0
The first number is the distance in cm that the block traveled when released from being pulled against a rubber band.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of two dominoes: **
2.21, 0
1.85, 0
1.85, 0
2.1, 0
These are the distances in cm traveled by the block during five trials. The rubber band was stretched to the distance that corresponds to the stretch is has under the weight of two dominoes. The block did not rotate during its slide.
** Rubber band lengths resulting in 5 cm, 10 cm and 15 cm slides: **
7.8, 8.05,8.38
These are the lengths in cm of the rubber band that resulted in slides of 5 cm, 10 cm and 15 cm.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of four dominoes: **
2.9, 1
2.7, 0
3.1, 1
3.4, 3
3.3, 1
These are the distances in cm and the rotation in degrees of a block as it slides after being released from being pulled against a rubber band. The band is stretched by a force that is equivalent to the weight of 4 dominoes.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of six dominoes: **
6.2, 2
6.4, 4
6.1, 1
6.0, 0
6.1, 1
These are the distances in cm and the rotation in degrees of a block as it slides after being released from being pulled against a rubber band. The band is stretched by a force that is equivalent to the weight of 6 dominoes.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of eight dominoes: **
7.6, 17
8, 5
8, 5
8.3, 7
9.1, 13
These are the distances in cm and the rotation in degrees of a block as it slides after being released from being pulled against a rubber band. The band is stretched by a force that is equivalent to the weight of 8 dominoes.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of ten dominoes: **
9.6, 0
12.8, 8
11.9, 8
14.3, 10
15.7, 10
These are the distances in cm and the rotation in degrees of a block as it slides after being released from being pulled against a rubber band. The band is stretched by a force that is equivalent to the weight of 10 dominoes.
** 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: **
7.56, 2, 1.962, .1816, 76.0
7.76, 4, 3.08, .224, 83.6
7.98, 6, 6.16, .1517, 60.8
8.14, 8, 8.2, .5612, 102.6
8.41, 10, 12.86, 2.329, 357.2
The energy is reported in ergs. The amount of energy associated with each stretch is the area under the force vs stretch curve for this rubber band, determined during calibration. The original units of this energy were in Newtons * cm. This number was multiplied by a conversion factor of 1000 to find the energy in ergs.
** 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: **
.03, 2.4
cm/erg, cm
The data points are somewhat scattered, so I looked at what Excel gives for regression. I have included the information from the line, but a quadratic equation fits better. The curve of that equation increases at a decreasing rate.
** Lengths of first and second rubber band for (first-band) tensions supporting 2, 4, 6, 8 and 10 dominoes: **
.014, 4.5
cm/erg, cm
The data points do not cluster around the line very much, as in the last graph. The graphs have very similar shapes, and both are better modeled by a curve that isn't straight.
** Mean sliding distance and std dev for each set of 5 trials, using 2 rubber bands in series: **
7.56, 7.8
7.76, 8.0
7.98, 8.3
8.14, 8.6
8.41, 8.9
** 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: **
2.69, .4068
4.39, .2068
7.42, .08367
13.14, .3049
14.32, .3834
** 1-band sliding distance and 2-band sliding distance for each tension: **
1.962, 2.69
3.08, 4.39
6.16, 7.42
8.2, 13.14
12.86, 14.32
** 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: **
3.2, -1.2
cm/cm, cm
These data points are well modeled by a line, they are all lie close to the regression line.
** 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 this experiment supports the hypothesis that the sliding distance is proportional to the energy required to stretch the rubber band. I do not think the proportionality is direct, though, I think there is a squared relationship. This agrees with what we've learned about the energy stored in a spring, too.
** How long did it take you to complete this experiment? **
I spent about 6 hours on this experiment, some of it due to errors and additional calculation for the replacement rubber band.
** Optional additional comments and/or questions: **
&#Your work looks very good. Let me know if you have any questions. &#