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): **
THis is a resubmission of my flow experiment, per your request. You are correct, I was incorrectly reporting time intervals and not clock times. My resubmission begins with the reporting of my depth vs clock times. I used the same timer data as in my first submission.
** Is flow rate increasing, decreasing, etc.? **
** Is the velocity of the water surface increasing, decreasing, etc.? **
** 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? **
** Explain how we know that a change in velocity implies the action of a force: **
** Does the depth seem to be changing at a regular rate, at a faster and faster rate, or at a slower and slower rate **
** What do you think a graph of depth vs. time would look like? **
** 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? **
** Does this distance change at an increasing, decreasing or steady rate? **
** What do you think a graph of this horizontal distance vs. time would look like? **
** The contents of TIMER program as you submitted them: **
1 7741.848 7741.848
2 7745.434 3.585938
3 7749.078 3.644531
4 7752.816 3.738281
5 7756.801 3.984375
6 7761.348 4.546875
7 7766.004 4.65625
8 7771.172 5.167969
9 7776.691 5.519531
10 7783.148 6.457031
11 7790.449 7.300781
12 7796.949 6.5
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
0
1.2cm
3.0cm
4.5 cm
6.3 cm
7.9 cm
9.5 cm
11.0 cm
12.7 cm
14.3 cm
15.6 cm
17.4 cm
** Your table for depth (in cm) vs clock time (in seconds) **
0,17.4
7745,15.6
7749,14.3
7752,12.7
7756,11.0
7761,9.5
7766,7.9
7771,6.3
7776,4.5
7783,3.0
7790,1.2
7796,0
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
It seems like the depth is changing at a slower and slower rate.
** Your description of your depth vs. t graph: **
The independent variable(x) is the clock time in seconds and the dependant variable(y) is the depth in cm. My intervals for the clock time start at 7740 and increase by 5 up to 7800.
Intervals for depth start at 2 and increase by 2 up to 18.
I then plotted each of my data points according to my table above.
My data points seem to be in a linear pattern. My best fit line seems to fit accurately through most of the data points.
** Your explanation and list of average average velocities: **
Average velocity is change in positon over change in time for each time interval.
.50 cm/s
.35
.42
.42
.33
.34 cm/s
.31
.32
.23
.24
.18
** The midpoints of your time intervals and how you obtained them: **
I took the added the clock times of each interval and divided by two to get the midpoint time interval.
7743
7747
7750
7754
7758
7763
7768
7773
7779
7786
7793
** Your table of average velocity of water surface vs. clock time: **
7743,.80
7747,.35
7750,.42
7754,.42
7758,.33
7763,.34
7768,.31
7773,.32
7779,.23
7786,.24
7793,.18
** Your description of your graph of average velocity vs clock time: **
Velocity is on my y axis, and Clock Time(midpoint time) is on my x axis.My intervals for the clock time start at 7740 and increase by 5 up to 7810. My intervals for the average velocity start at .10 and increase by 5 up to .80.
It seems like my data points seem to form a curve, similiar to an upside down parabola, but it's not as pronounced, so it is more of a curve.
** Your explanation of how acceleration values were obtained: **
average accelaration is change in velocity divided by midpoint time of each time interval.
** Your acceleration vs clock time table: **
7743,.00010 cm/s^2
7747,.00004
7750,.00005
7754,.00005
7758,.00004
7763,.00004
7768,.00003
7773,.00004
7779,.00002
7786,.00003
7793,.00002
average acceleration is change in velocity / change in clock time over an observed interval. None of your time intervals exceeds 10 seconds.
It looks like you divided by the clock time, not by the change in clock time. Your calculation would depend on when you happened to make the first click. Had you started the timer within the first 100 seconds your results would have been much different. However the average velocities and average accelerations over these intervals would have been the same, indicating the flaw in your results.
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
My data indicates that the acceleration on the water surface is decreasing.
I think the acceleration on the water surface is actually decreasing as well. The water surface seems to be decelerating because the velocity is getting slower.
Good work, except for the acceleration information.
While you would report your original data, you wouldn't report a clock time of 0, then clock times ranging from about 7700 to 7800 seconds. The interval from 0 sec to 7700 sec is not part of what was measured.
Generally when reporting clock times, you assume a clock that read 0 when the event occurred. You should report your original data, but then convert to this hypothetical clock. So for example instead of running from 7743 to 7796 sec your clock would run from 0 to 53 sec.
You could for example relabel the horizontal axis of your v vs. t graph (replacing 7743 by 0 and 7796 by 53 sec, etc.) without changing any of your velocity results, which appear to be good.
No need to redo anything except your calculations of acceleration. Please resubmit, starting with your velocity vs. clock time information.