Phy 122
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 the flow rate to remain the same based on the equal time interval and, above where each picture captures half of the previous amount.
** Is the velocity of the water surface increasing, decreasing, etc.? **
At first response, I would expect the velocity of the water surface and buoy to follow the rate of flow of the water in the cylinder. But I think it actually increase because of the pressure on the surface of the water pushing it out (the water is falling due to gravity).
** 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 diamter of the hole for the exiting water will indicate the velocity of the exiting water. The velocity of the surface of the water depends on the force per unit of length (or depth) of the cylinder. The force will depend on the diamter of the cylinder itself.
** Explain how we know that a change in velocity implies the action of a force: **
A change in velocity is indicated by the average acceleration and the change in time interval. The acceleration in the cylinder is due to gravity (the force exerted on the water to push it downward and out of the cylinder) which increases the water velocity.
** 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 of the water changes at a regular rate based on the equal time interval and the view of the pitcures. The experiment may present a different result, but this is the outcome I expect at this point. It seems that the water is half the amount of the previous picture of each picture, and therefore, reasons that it would be flowing constantly at a regular rate.
** What do you think a graph of depth vs. time would look like? **
The x-axis would be time vs. y-axis which would be depth. As the time interval increases, the depth decreases. It would be a negative slope graph.
** 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 stream decreases as time goes on.
** Does this distance change at an increasing, decreasing or steady rate? **
The distance changes at a steady rate.
** What do you think a graph of this horizontal distance vs. time would look like? **
The x-axis would be time vs. the y-axis which would be horizontal distance. If time is a constant increasing interval and distance decreases as the force of the water is decreasing, then the graph depicts a negative slope toward zero on the graph.
** The contents of TIMER program as you submitted them: **
1 754.6953 754.6953
2 756.3359 1.640625
3 758.9063 2.570313
4 761.2813 2.375
5 764.2109 2.929688
6 767.1484 2.9375
7 770.3203 3.171875
8 773.9453 3.625
9 777.5234 3.578125
10 784.4844 6.960938
11 790.0781 5.59375
12 798.3281 8.25
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
1.5cm
3.2cm
4.7cm
6.2cm
7.7cm
9.2cm
10.7cm
12.2cm
13.7cm
15.2cm
16.7cm
** Your table for depth (in cm) vs clock time (in seconds) **
0,16.7
1.64,15.2
4.21,13.7
6.59,12.2
9.52,10.7
12.45,9.2
15.62,7.7
19.25,6.2
22.83,4.7
29.79,3.2
35.38,1.5
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
The depth is changing at a slower and slower rate.
** Your description of your depth vs. t graph: **
The y-axis is labeled water depth (cm); the x-axis is labeled clock time (s); both are labeled in by 2 point intervals (i.e. 2, 4, 6, 8...20). The first point is marked at zero on the x-axis and 16.7cm on the y-axis. From this point, the graph assumes a negative slope. The points (6.59,12.2) and (12.45,9.2) flatted the graph, indicating and decrease in flow rate of the water. If a best-fit line is draw for this graph, it will pass through the points (0,16.7) and (12.45,9.2).
** Your explanation and list of average average velocities: **
To find the average velocity of the water surface, I divided the displacement - final position-initial position - (in meters, after converting all cm values to m) by the elapsed time (in seconds).
The first value is undefined because we started at zero.
.0927 m/s
.0325 m/s
.0185 m/s
.0112 m/s
.0074 m/s
.0049 m/s
.0032 m/s
.0021 m/s
.0011 m/s
.000424 m/s
** The midpoints of your time intervals and how you obtained them: **
From zero seconds of the initial position of the water to 1.64 seconds when the water had decreased from 16.7cm above the outflow hole to 15.2cm, the midpoint of that interval would be 0.82 seconds. The second midpoint would occur at 2.93 seconds. (This value was obtained by adding 1.64seconds + 4.21seconds and dividing by 2. The 1.64s is at 15.2cm above the outflow hole. The midpoint between this point and the next (4.21 seconds at 13.7cm above outflow hole) is 2.93seconds.
The other midpoints are:
5.40s
8.05s
10.99s
14.04s
17.44s
21.04s
26.31s
32.59s
** Your table of average velocity of water surface vs. clock time: **
1.64s,0.0927m/s
4.21s,0.0325m/s
6.59s,0.0185m/s
9.52s,0.112m/s
12.45s,0.0074m/s
15.62s,0.0049m/s
19.25s,0.0032m/s
22.83s,0.0021m/s
29.79s,0.0011m/s
35.38s,0.000424m/s
** Your description of your graph of average velocity vs clock time: **
The clock time is on the x-axis and the avg. velocity is on the y-axis. as the time increases, the velocity decreases. The graph tends to flatten out at 12.45s with a velocity of 0.0074m/s because the water is flowing at a slower rate and velocity decreases.
** Your explanation of how acceleration values were obtained: **
I obtained average acceleration by dividing the change in velocity of 1.64s and 4.21s (.0602m/s) by the difference of that time interval (2.57s).
So the first avg. acceleration is 0.0602m/s / 2.57s = 0.0234m/s^2.
** Your acceleration vs clock time table: **
2.93,0.234m/s^2
5.40,0.0059m/s^2
8.05,0.0025m/s^2
10.99,0.0013m/s^2
14.04,0.000789m/s^2
17.44,0.000468m/s^2
21.04,0.000307m/s^2
26.31,0.000144m/s^2
32.59,0.000121m/s^2
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
The data above indicates that the acceleration of the water surface is decreasing at a constant rate.
I think the acceleration of the water surface actually does decrease.
** **
3 hours
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