phy121
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: **
12:45
** 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? **
3.35, 0
This is the distance the block traveled and the angle it ended up at.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of two dominoes: **
2.27, 10
3, 0
2.6, 10
2.6, 10
3.1, 0
These are the distances traveled and the apox. angle they stopped at.
** Rubber band lengths resulting in 5 cm, 10 cm and 15 cm slides: **
7.9, 8.15, 8.3
These are the lengths of the rubber band, at which it caused the block to travel a distance of 5, 10, and 15cm after release respectivly.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of four dominoes: **
6.6, 0
6.6, 0
5.7, 0
6.4, 0
6.5, 0
These are the lengths of travel when the block was pulled back the length required to hold 4 dominoes.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of six dominoes: **
10.5, 20
10, 20
10.1, 20
10.6, 25
10.7, 20
These are the lengths of travel and angle when the block was pulled back the length required to hold 6 dominoes.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of eight dominoes: **
13.2, 10
12.6, 10
13.95, 10
13.7, 5
12.8, 5
These are the lengths of travel and angle when the block was pulled back the length required to hold 8 dominoes.
** 5 trials, distance in cm then rotation in degrees, with rubber band tension equal to the weight of ten dominoes: **
18.75, 20
19, 20
19.25, 20
20.6, 20
19.5, 0
These are the lengths of travel and angle when the block was pulled back the length required to hold 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: **
7.75, 2, 2.714, .3369, .053
8, 4, 6.36, .3782, .3
8.25, 6, 10.38, .3114, .73
8.5, 8, 13.25, .5745, 1.35
8.85, 10, 19.42, .7164, 2.36
My energy is reported in Newton * cm's. I got this by subtracting the length at which the band was taught, but not exibiting any force from the lenght of each desired weight and multiplying that by the ammount of force at that length.
Example:
(desired lenght - min. taught lenght) * Fatlenght = N*cm
(7.75cm - 7.61cm) * .38N = .0532N*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: **
6.83, 3.877
slope has no units, verticle intercept is in distance in cm
My points fit the line ok, but it would appear that the line is increasing at a decreasing rate due to the face that the first and last two data points are below the line, and the ones between them are above.
To get the slope you need to divide the rise between two points by the run. For example, if the points (.5 N * cm, 7 cm) and (2.5 N * cm, 19.4 cm) are on the graph the slope would be rise / run = 12.4 cm / (2 N * cm) = 6.2 N^-1, where N^-1 means 1/N. Your number is right, but your slope does have units.
** Lengths of first and second rubber band for (first-band) tensions supporting 2, 4, 6, 8 and 10 dominoes: **
6.0747, 8.4048
Slope has no units, and the vertical intercept is in cm
They cluster much closer in this graph than the last and seem to exibit a curvature.
The curvature would appear to be in the increasing at a decreasing rate.
** Mean sliding distance and std dev for each set of 5 trials, using 2 rubber bands in series: **
7.75, 7.5
8, 7.8
8.25, 8.1
8.5, 8.2
8.85, 8.5
** 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: **
6.81, .5389
11.84, .3049
17.55, 1.065
22.6, .6892
32.4, .6354
** 1-band sliding distance and 2-band sliding distance for each tension: **
2.714, 6.81
6.36, 11.84
10.38, 17.55
13.25, 22.6
19.42, 32.4
** 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: **
1.5398, 2.1883
slope has no units, y-intercept is in cm
The points are very close to the line and indicate a straight line relationship.
** 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 what we did here supports this. I believe this because when we added the 2nd rubber band, the amount of energy needed to strech them increased. It didn't exactly double (and in one instance decreased, but I believe this is due to errors in the values I was using for lenghts of rubber bands) and I believe that thermal losses and friction were both at work here.
** How long did it take you to complete this experiment? **
1hr 45min
** Optional additional comments and/or questions: **
&#Good work. See my notes and let me know if you have questions. &#