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 rate of flow to decrease.
** Is the velocity of the water surface increasing, decreasing, etc.? **
I expect the velocity of the water surface to stay the same.
** 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 water surface is lesser than that of the exiting water because the diameter through which the liquid moves through the cylinder is greater than through the hole.
** Explain how we know that a change in velocity implies the action of a force: **
A change in velocity implies an action of a force because we know that if there is no force acting on something, then it's motion doesn't change. If no force acts to accelerate, then no acceleration occurs.
** Does the depth seem to be changing at a regular rate, at a faster and faster rate, or at a slower and slower rate **
I think the nature of the force is pressure. The depth seems to be changing at a regular rate.
** What do you think a graph of depth vs. time would look like? **
The graph would be of a line that has a downward slope as it travels down toward the x axis.
** 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 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 change at an increasing rate.
** What do you think a graph of this horizontal distance vs. time would look like? **
The graph of the horizontal distance would also be a line that has a downward slope as it travels down toward the x axis.
** The contents of TIMER program as you submitted them: **
1 195.7656 195.7656
2 198.5 2.734375
3 201.3438 2.84375
4 204.5156 3.171875
5 207.875 3.359375
6 211.5 3.625
7 215.5625 4.0625
8 219.9844 4.421875
9 224.7656 4.78125
10 230.5469 5.78125
11 238.1719 7.625
12 243.8281 5.65625
13 251.2188 7.390625
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
.6 cm
2.2 cm
3.8 cm
5.4 cm
6.9 cm
8.5 cm
10.0 cm
11.5 cm
12.9 cm
14.4 cm
15.9 cm
17.3 cm
** Your table for depth (in cm) vs clock time (in seconds) **
0, 17.3
2.73, 15.9
5.57, 14.4
8.74, 12.9
12.1, 11.5
15.73, 10.0
19.79, 8.5
24.21, 6.9
28.99, 5.4
34.77, 3.8
42.4, 2.2
48.06, .6
55.45, 0
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
The depth was changing at a regular rate like I expected.
** Your description of your depth vs. t graph: **
The graph has a downward slope as it approaches the x axis. This is what I initially expected as well.
** Your explanation and list of average average velocities: **
For each time interval, I found the distance by finding the difference between each preceding one and I divided that distance by the time interval.
Example:17.3 - 15.9 = 1.4
1.4/ 2.73 = .51 cm/s = .0051 m/s
.0051 m/s
.0052 m/s
.0047 m/s
.0042 m/s
.0045 m/s
.0037 m/s
.0036 m/s
.0031 m/s
.0028 m/s
.0021 m/s
.0028 m/s
.0008 m/s
** The midpoints of your time intervals and how you obtained them: **
1.37
1.42
1.59
1.68
1.82
2.03
2.21
2.39
2.89
3.82
2.83
3.70
I obtained these values by finding the difference between each clock time intervals and then dividing that difference by 2 to get the midpoint. Example: (2.73-0)/2 = 1.37
(5.57-2.73)/2 = 1.42
(8.74-5.57)/2 = 1.59
I am unsure if I did that correctly, however.
Your clock times run from 0 sec to over 50 sec. The midpoint between two clock times is the clock time halfway between the two.
For example you report consecutive clock times of 28.99 s and 34.77s. The midpoint clock time would be between 11 and 12 seconds; just average the two clock times.
** Your table of average velocity of water surface vs. clock time: **
1.37, 0.0051
1.42, 0.0052
1.59, 0.0047
1.68, 0.0042
1.82, 0.0045
2.03, 0.0037
2.21, 0.0036
2.39, 0.0031
2.89, 0.0028
3.82, 0.0021
2.83, 0.0028
3.7, 0.0008
** Your description of your graph of average velocity vs clock time: **
The graph also has a downward slope as it approaches the x axis.
** Your explanation of how acceleration values were obtained: **
.0070 m/s^2
.0074 m/s^2
.0075 m/s^2
.0071 m/s^2
.0082 m/s^2
.0075 m/s^2
.0080 m/s^2
.0074 m/s^2
.0081 m/s^2
.0080 m/s^2
.0079 m/s^2
.0030 m/s^2
I obtained these values by multiplying each average velocity by the clock time. Example: 1.37 s * .0051 m/s = .0070 m/s^2
The units of s * m/s are m, not m/s^2. So this calculation cannot be correct.
Acceleration is change in velocity / change in clock time. You would find the difference of consecutive average velocities and divide by the difference between the midpoint clock times.
** Your acceleration vs clock time table: **
1.37, 0.007
1.42, 0.0074
1.59, 0.0075
1.68, 0.0071
1.82, 0.0082
2.03, 0.0075
2.21, 0.008
2.39, 0.0074
2.89, 0.0081
3.82, 0.008
2.83, 0.0079
3.7, 0.003
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
It seems that the acceleration of the water surface did roughly stay about the same. So I think it's safe to say that that the acceleration was constant.
The graph of depth vs. clock time decreases at a decreasing rate, and this is consistent with the decreasing velocity you report. Your description of the depth vs. clock time graph as apparently linear is not correct; did you use a consistent scale for your t axis?
Your calculations of midpoint clock time and acceleration are not correct. Be sure to see my notes.