Phy 231
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? **
1.82, 0
The first number is the distance the domino block moved relative to the initial position of the block at a pull back of 8.35 cm. The second number is the number of degrees the block rotated: my block did not rotate.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of two dominoes: **
2.7, 0
1.93, 0
1.8, 0
2.57, 0
3.25, 0
These numbers were obtained by pulling the block back so that the rubber band was stretched to the length of 8.35 cm and then releasing. The first number is the distance travelled by the block. The second number is the number of degrees rostated by the block.
** #$&* Rubber band lengths resulting in 5 cm, 10 cm and 15 cm slides: **
8.4, 9.1, 9.4
-
These numbers are the lengths of the rubber band needed for the block to slide 5, 10 and 15 cm respectively.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of four dominoes: **
6.15, 0
6.59, 5
5.7, 5
6.35, 10
6.75, 0
These are the distances travelled by the block past the intial point with a rubber band stretch of 8.61 cm.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of six dominoes: **
8.66, 0
7.57, 10
9.1, 5
7.95, 0
8.15, 0
These are the distances travelled by the block past the intial point with a rubber band stretch of 8.79 cm.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of eight dominoes: **
12.45, 0
10.4, 5
11.69, 10
11.51, 0
11.55, 5
These are the distances travelled by the block past the intial point with a rubber band stretch of 9.04 cm.
** #$&* 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of ten dominoes: **
15.75, 5
16.6, 0
14.67, 0
15.5, 10
14.3, 0
These are the distances travelled by the block past the intial point with a rubber band stretch of 9.27 cm.
** #$&* Rubber band length, the number of dominoes supported at this length, the mean and the standard deviation of the sliding distance in cm, and the energy associated with the stretch, for each set of 5 trials: **
8.35, 2, 2.345, .59, .0855
8.61, 4, 6.308, .4097, .2698
8.79, 6, 8.286, .6014, 1.0146
9.04, 8, 11.52, .733, 1.7328
9.27, 10, 15.36, .9095, 2.603
The energy is given in N cm. You calculate the energy by multiplying the amount of energy needed to stretch the band the length by the distance over which the force is applied (the stretched length of the rubber band minus the original length).
** #$&* 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: **
3.49, 3.2
slope: N, intercept: cm
The data points are pretty close to the line, but they do not follow a linear graph very well. Some curvature of the graph would make the points fit better. The curve seems to indicate a concave down graph.
** #$&* Lengths of first and second rubber band for (first-band) tensions supporting 2, 4, 6, 8 and 10 dominoes: **
3.75, 6.5
Slope: N, y-intercept: cm
The data points are close around the line. They seem to be more linear than the first set, but the line curves a little bet. It seems like a concave down graph would fit the data better.
** #$&* Mean sliding distance and std dev for each set of 5 trials, using 2 rubber bands in series: **
8.35, 8.4
8.61, 8.55
8.79, 8.75
9.04, 9.25
9.27, 9.6
** #$&* Slope and vertical intercept of straight-line approximation to sliding distance vs. energy, units of slope and vertical intercept, description of the graph and closeness to line, any indication of curvature: **
6.038, .3959
11.73, .8822
14.58, .8291
26.77, 1.218
31, .6042
** 1-band sliding distance and 2-band sliding distance for each tension: **
2.345, 6.038
6.308, 11.73
8.286, 14.58
11.52, 26.77
15.36, 31
** #$&* 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: **
1.78, 3.7
Slope: no units; intercept: cm
The points stay pretty close around the straight line. The graph could either be linear or it could be convace up
** #$&* Discussion of two hypotheses: 1. The sliding distance is directly proportional to the amount of energy required to stretch the rubber band. 2. If two rubber bands are used the sliding distance is determined by the total amount of energy required to stretch them. **
I think the results support this hypothesis. When the rubber bands were stretched more, there was more elastic potential energy. This, in turn, made the block slide farther.
A direct proportion implies a linear graph through the origin. Your data are not conclusive on this, but this is to be expected. The nature of neither the frictional force nor the rubber band force would be expected to exhibit ideal behavior, so there is a lot of uncertainty built into the experiment.
** #$&* How long did it take you to complete this experiment? **
1 hour, 30 minutes
** #$&* Optional additional comments and/or questions: **
&#Good responses. See my notes and let me know if you have questions. &#
I apologize for the delayed posting of this file. I completed my review on 7/3, but the posting process apparently went awry and it is being posted two days late. It might therefore be a little out of order on your access page.