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 expect that the rate of flow would decrease.
** Is the velocity of the water surface increasing, decreasing, etc.? **
The downward velocity of the buoy would decrease as the water level decreased.
** 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? **
The velocity of the fluid only depends on the pipe diameter (diameter of the hole), the viscostiy of the fluid, and the pressure gradient (also known as the pressure drop). So the bigger the hole the faster the velocity. The greater the preasure head (deeper the water) the faster the velocity. If the water has a greater surface area, that means there is probably a larger volume of water, so at a given velocity it will take longer for the volume to decrease.
** Explain how we know that a change in velocity implies the action of a force: **
If there is a change in velocity, some kind of acceleration had to have taken place. If there was acceleration and mass, there must have been a force.
F = m * a.
** 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 slower rate. You can see this because the difference high from the first to the second picture is about half. From the second to the third picture it is clearly more than half.
** What do you think a graph of depth vs. time would look like? **
I think a graph of depth vs. time would start with a steep slope, but as depth went to zero, the slope would go to zero.
** 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 horizontal distance decreases as time goes on. This makes sense because as the depth decreases, pressure decreases. With less pressure, there is less force pushing the water out of the cylinder.
** Does this distance change at an increasing, decreasing or steady rate? **
At a decreasing rate for the same reasons as stated above.
** What do you think a graph of this horizontal distance vs. time would look like? **
The graph would look somewhat parabolic I think. At time equals zero, the graph would be at its maximum. As time moved on it would decrease at an increasing rate to a distance of zero.
** The contents of TIMER program as you submitted them: **
1 85.25 85.25
2 86.07813 .828125
3 87.1875 1.109375
4 88.5 1.3125
5 89.5625 1.0625
6 90.82813 1.265625
7 92.15625 1.328125
8 93.40625 1.25
9 94.79688 1.390625
10 96.20313 1.40625
11 97.59375 1.390625
12 99.40625 1.8125
13 100.75 1.34375
14 102.5469 1.796875
15 104.4219 1.875
16 106.4219 2
17 108.8125 2.390625
18 110.7969 1.984375
19 114.125 3.328125
20 117.5156 3.390625
21 122.3594 4.84375
22 126.4844 4.125
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
(Measurements in cm)
0.4
1.2
2.0
2.8
3.6
4.4
5.2
6.0
6.8
7.6
8.4
9.2
10.0
10.8
11.6
12.4
13.2
14.0
14.8
15.6
16.4
17.2
** Your table for depth (in cm) vs clock time (in seconds) **
0,16.4
0.82813,15.6
1.9375, 14.8
3.25, 14
4.3125, 13.2
5.57813,12.4
6.90625,11.6
8.15625,10.8
9.54688,10
10.95313,9.2
12.34375,8.4
14.15625,7.6
15.5, 6.8
17.2969,6
19.1719,5.2
21.1719,4.4
23.5625,3.6
25.5469,2.8
28.875, 2
32.2656,1.2
37.1094,0.4
41.2344,0
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
The data supported my answer from above.
** Your description of your depth vs. t graph: **
The graph is decreasing at a slower and slower rate, much like I predicted above.
** Your explanation and list of average average velocities: **
I did rise over run for each time.
These numbers are in cm/s.
-0.966031903
-0.721130011
-0.60952381
-0.752941176
-0.632096268
-0.602355209
-0.64
-0.57527883
-0.568888889
-0.575282967
-0.44137931
-0.595348837
-0.445211197
-0.426666667
-0.4
-0.334644022
-0.403144527
-0.240377393
-0.23594644
-0.165159585
-0.096969697
** The midpoints of your time intervals and how you obtained them: **
I found the clock times of the midpoints by going halfway between each time point. This data is in seconds.
0.414065
1.382815
2.59375
3.78125
4.945315
6.24219
7.53125
8.851565
10.250005
11.64844
13.25
14.828125
16.39845
18.2344
20.1719
22.3672
24.5547
27.21095
30.5703
34.6875
39.1719
** Your table of average velocity of water surface vs. clock time: **
0.414065, -0.966031903
1.382815, -0.721130011
2.59375, -0.60952381
3.78125, -0.752941176
4.945315, -0.632096268
6.24219, -0.602355209
7.53125, -0.64
8.851565, -0.57527883
10.250005, -0.568888889
11.64844, -0.575282967
13.25, -0.44137931
14.828125, -0.595348837
16.39845, -0.445211197
18.2344, -0.426666667
20.1719, -0.4
22.3672, -0.334644022
24.5547, -0.403144527
27.21095, -0.240377393
30.5703, -0.23594644
34.6875, -0.165159585
39.1719, -0.096969697
** Your description of your graph of average velocity vs clock time: **
If you take the absolute values of the velocities, the velocity is decreasing at a decreasing rate.
** Your explanation of how acceleration values were obtained: **
I used the same method that was used for finding the velocity, rise over run.
** Your acceleration vs clock time table: **
0.89844, 0.252801954
1.9882825 0.092165311
3.1875, -0.12077252
4.3632825, 0.103812853
5.5937525, 0.022932865
6.88672, -0.029203289
8.1914075, 0.049019491
9.550785, 0.004569336
10.9492225, -0.00457231
12.44922, 0.083608268
14.0390625, -0.097564849
15.6132875, 0.095609278
17.316425, 0.010100782
19.20315, 0.013763441
21.26955, 0.029770864
23.46095, -0.031314517
25.882825, 0.061277039
28.890625, 0.001318991
32.6289, 0.01719296
36.9297, 0.015206023
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
The results are inconclusive. The data is too jagged.
** **
About an hour.
&#Very good responses. Let me know if you have questions. &#