Phy 232
Your 'flow experiment' 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 initial message (if any): **
** Is flow rate increasing, decreasing, etc.? **
I would expect the rate of flow to decrease because as the depth decreases the pressure also decreases. This would cause the flow rate out of the cylinder to decrease as well.
** Is the velocity of the water surface increasing, decreasing, etc.? **
I would expect the velocity of the water surface to decrease as the buoy descends because I expect the flow rate leaving the tube to decrease as well.
** How would the velocity of the water surface, the velocity of the exiting water, the diameter of the cylinder and the diameter of the hole be interrelated? **
Set the flow rate of the water surface equal to the flow rate of the water exiting the tube. The velocity of the water surface would be = (velocity leaving tube *diameter of hole)/(diameter of tube).
** Explain how we know that a change in velocity implies the action of a force: **
Using Newtons first law, we know that for any body to accelerate (or a change in velocity to occur) a force must be applied to that object.
** Does the depth seem to be changing at a regular rate, at a faster and faster rate, or at a slower and slower rate **
The depth seems to be changing at a regulat rate.
** What do you think a graph of depth vs. time would look like? **
Since there is no evident acceleration to the changing water level, the graph would be approximately linear.
** Does the horizontal distance (the distance to the right, ignoring the up and down distance) traveled by the stream increase or decrease as time goes on? **
The distance traveled by the stream seems to decrease as time goes on.
** Does this distance change at an increasing, decreasing or steady rate? **
The distance seems to decrease at an increasing rate.
** What do you think a graph of this horizontal distance vs. time would look like? **
I would expect the graph to be parabolic because the rate of distance will change over time.
** The contents of TIMER program as you submitted them: **
1 327.0156 327.0156
2 328.3125 1.296875
3 329.6719 1.359375
4 331.2656 1.59375
5 332.6094 1.34375
6 334.1719 1.5625
7 335.625 1.453125
8 337.2656 1.640625
9 338.8594 1.59375
10 340.5938 1.734375
11 342.25 1.65625
12 343.9844 1.734375
13 345.6875 1.703125
14 347.5625 1.875
15 349.4063 1.84375
16 351.5 2.09375
17 353.4688 1.96875
18 355.5938 2.125
19 357.7031 2.109375
20 360.0938 2.390625
21 362.4375 2.34375
22 365.2813 2.84375
23 367.6094 2.328125
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
6 mm
16
26
36
46
56
66
76
86
96
106
116
126
136
146
156
166
176
186
196
206
216
226
** Your table for depth (in cm) vs clock time (in seconds) **
0, 226
1.30, 216
2.66, 206
4.25, 196
5.59, 186
7.16, 176
8.61, 166
10.25, 156
11.84, 146
13.58, 136
15.23, 126
16.97, 116
18.67, 106
20.55, 96
22.39, 86
24.48, 76
26.45, 66
28.58, 56
30.69, 46
33.08, 36
35.42, 26
38.27, 16
40.59, 6
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
The depths are changing at a slower and slower rate. This contradicts my observation above, but it makes sense because as the depth decreases the pressure decreases.
** Your description of your depth vs. t graph: **
I would say that the graph is polynomial because it can be observed that the slope of the curve changes constantly. Since the curvature is very small, the order of it would be between two and one.
** Your explanation and list of average average velocities: **
The average velocity can be found by dividing the distance traveled by the water level, by the amount of time which expired over that interval.
I used the difference quotient capability of the data program to analyze this for me. Below are my midpoints vs. velocities.
Your table shows velocities vs. midpoints, which is as requested
.65,-7.692
1.98,-7.353
3.455,-6.289
4.92,-7.463
6.375,-6.369
7.885,-6.897
9.43,-6.098
11.05,-6.289
12.71,-5.747
14.41,-6.061
16.1,-5.747
17.82,-5.882
19.61,-5.319
21.47,-5.435
23.44,-4.785
25.47,-5.076
27.52,-4.695
29.64,-4.739
31.89,-4.184
34.25,-4.274
36.85,-3.509
39.43,-4.310
** The midpoints of your time intervals and how you obtained them: **
.65
1.98
3.455
4.92
6.375
7.885
9.43
11.05
12.71
14.41
16.1
17.82
19.61
21.47
23.44
25.47
27.52
29.64
31.89
34.25
36.85
39.43
** Your table of average velocity of water surface vs. clock time: **
.65,-7.692
1.98,-7.353
3.455,-6.289
4.92,-7.463
6.375,-6.369
7.885,-6.897
9.43,-6.098
11.05,-6.289
12.71,-5.747
14.41,-6.061
16.1,-5.747
17.82,-5.882
19.61,-5.319
21.47,-5.435
23.44,-4.785
25.47,-5.076
27.52,-4.695
29.64,-4.739
31.89,-4.184
34.25,-4.274
36.85,-3.509
39.43,-4.310
** Your description of your graph of average velocity vs clock time: **
The graph of average velocity vs. time is a little choppy but you can tell it is linear. The slope of the graph is positive, but this is only because my velocity values are negative due to the decreasing water level. If the velocities were positive then you would be able to tell that as the time increases the velocities get smaller.
** Your explanation of how acceleration values were obtained: **
The acceleration values are obtained by finding the change of the velocity of the water level over time. To do this I took the difference quotient of the velocity vs. midpoint values, the results are shown below.
** Your acceleration vs clock time table: **
1.315,-.2549
2.718,-.7214
4.188, .8014
5.648,-.7519
7.13, .3497
8.658,-.5172
10.24, .1179
11.88,-.3265
13.56, .1847
15.26,-.1858
16.96, 0.07849
18.72,-.3145
20.54, 0.06237
22.46,-.3299
24.46, .1433
26.49,-.1859
28.58, 0.02075
30.77,-.2467
33.07, 0.03814
35.55,-.2942
38.14, .3105
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
The results are inconclusive. When the data is graphed it is hard to decipher any trend. The accelerations are constantly deviating from positive to negative. This could be due to friction in the cyclinder, experimental errors, or something of that nature.
** **
2.5 hours
&#This looks very good. Let me know if you have any questions. &#