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? **
8.5 cm, 10 degrees
The block moved 8.5 cm after being released from the pullback position. It rotated about 10 degrees.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of two dominoes: **
8.5, 10
6, 10
6.7, 10
9.6, 10
8, 10
The dominoes usually only rotated about 10 degrees above or below the horizontal. The distance of travel varied greatly over the interval.
** Rubber band lengths resulting in 5 cm, 10 cm and 15 cm slides: **
7.2, 8.8, 9.4
These are the lengths corresponding to sliding distances of 5,10 and 15 cm.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of four dominoes: **
8.8, 10
9.1, 15
8.6, 10
9.4, 15
9.5, 15
These are the lengths and angles of the sliding distances.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of six dominoes: **
8.9, 15
8.8, 15
9.8, 15
10.2, 20
10, 20
These are the lengths and angles of the sliding distances.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of eight dominoes: **
14, 25
15, 50
15.2, 45
12.8, 30
14.4, 45
These are the lengths and angles of the sliding distances.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of ten dominoes: **
25,45
27, 30
30, 40
27, 45
24, 45
These were the lengths and the angles of rotations of the 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: **
7.6, 4, 9.08, .3834, 6.9
7.8, 6, 9.54, .6465, 10.88
8.2, 8, 14.28, .9549, 21.71
8.8, 10, 26.6, 2.302, 50.54
The units of energy (last column) are recorded in N*cm. They were recorded by multiplying the mean distance found by the force. The force corresponds to the number of dominoes used. This was calculated in a previous lab. It comes out to about .19N per domino.
** 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: **
2.5, -12
The slope would be in N*cm / cm. This makes the units N. The y intercept would be in N*cm I suppose since the x-coordinate value is 0.
From the graph I drew, it looks as if the line could be straight. You cannot positively tell if there will be curvature. I think this is because of the large axes I drew. If I was to guess that there would be curvature, I would assume that it curves upwards.
** Lengths of first and second rubber band for (first-band) tensions supporting 2, 4, 6, 8 and 10 dominoes: **
5, -20
The units would be N for slope and N*cm for y-intercept.
My data points follow the line relatively well, only showing a hint of curvature.
Curvature is better indicated this time, I think from using a smaller data set for the axes, and it looks as if there is downward concavity.
** Mean sliding distance and std dev for each set of 5 trials, using 2 rubber bands in series: **
7.2, 7.2
7.4, 7.2
8.0, 7.4
8.5, 7.6
** 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: **
9.42, .3427
9.93, .5268
15.4, 1.253
25.2, 2.465
** 1-band sliding distance and 2-band sliding distance for each tension: **
9.08, 9.42
9.54, 9.93
14.28, 15.4
26.6, 25.2
** 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: **
0.94, 0
The slope would be unitless since both the x and y axes are in the same units. The y-intercept would be in cm.
The numbers from the table were very similar since I did not see much of a difference between one and two rubber bands. Therefore, this gave me a slope that was very close to 1. Curvature is not 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. **
I would agree with this hypothesis but I'm not sure how far my results go to support it. Since there was a great deal of uncertainty in performing this experiment, especially getting the rubber bands to stretch to the same length consistently.
** How long did it take you to complete this experiment? **
2 hours
** Optional additional comments and/or questions: **
&#Your work looks very good. Let me know if you have any questions. &#