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.? **
As the water flows from the cylinder, I would expect the rate of flow to increase, due to the force of gravity.
** Is the velocity of the water surface increasing, decreasing, etc.? **
I would expect the velocity of the water surface/buoy to increase because thea rate of flow is accelerating. I assume that they are related and I would guess that it's a directly proportional relationship.
** 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 diameter of the cylinder and the diameter of the hole will affect the velocity of the water surface and the existing water. I think that the larger the cylinder and diameter of of the hole, the smaller the velocity of the water surface and exisiting water will be..there's an inverse relationship.
** Explain how we know that a change in velocity implies the action of a force: **
The change in velocity is acccleration. Given Newton's laws, F=ma, we know that when there is acceleration, there must be a net force that causes that acceleration.
** Does the depth seem to be changing at a regular rate, at a faster and faster rate, or at a slower and slower rate **
It seems from the pics that the depth is changing at a regular rate.
** What do you think a graph of depth vs. time would look like? **
I beleive that depth and time would have an inverse relationship, and since the rate of flow is steady, the depth of flow would change by the same amount per unit of time. The graph would be a straight line.
** 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? **
I think the horizontal distance would decrease as seen from the pics.
** Does this distance change at an increasing, decreasing or steady rate? **
This distance seems like it would change at a decreasing rate, steadily getting shorter and shorter until there's no more liquid left in the cylinder.
** What do you think a graph of this horizontal distance vs. time would look like? **
Horizontal distance would be plotted on the dependant, y axis and time would be plotted on the independant x axis. There seems to be an inverse relationship between these two values also.
** 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
3.58,15.6
3.64,14.3
3.73,12.7
3.98,11.0
4.54,9.5
4.65,7.9
5.16,6.3
5.51,4.5
6.45,3.0
7.30,1.2
6.50,0
This graph appears to report depth ve. time interval, not depth vs. clock time.
&#You appear to be reporting depth vs. time interval, not depth vs. clock time.For example if clock times are 2, 5, 15 and 17 seconds, then the time intervals are respectively 3, 10 and 2 seconds. The latter are time intervals, not clock times. The clock starts at the beginning of the observation and continues running through the end, and clock times are the times showing on the clock. The clock cannot run backward, so clock times cannot decrease, whereas time intervals can either increase or decrease.
&#
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
From the data, it seems like the depth is changing at a slower and slower rate; that contradicts my answer of a regular rate above.
** 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 are:
2,2.5,3,3.5,4,4.5,5,5.5,6,6.5,7,7.5
Intervals for depth are the values are:
2,4,6,8,10,12,14,16,18
I then plotted each of my data points according to my table above.
The data points are not in a straight line as I expected. The best fit line has many data points above and below it.
** 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
21.6
17.7
6.8
2.14
14.5
3.13
5.14
1.59
2.11
1.50
I kept these values in cm/s for simplicty but I realize that velocity is in m/s and we would have to convert from cm to meters to be completely accurate.
cm/s is a valid unit and appropriate to this report
** The midpoints of your time intervals and how you obtained them: **
I obtained the midpoint of the time interval, by taking the change in time in each interval and dividing by two.
1.79s
.030
.045
.125
.280
.055
.255
.175
.470
.425
.400
&#However your first column cannot indicate midpoint clock times. You might be reporting half the time interval, but time intervals and clock times are two different things.For example if clock times are 2, 5, 15 and 17 seconds, then the time intervals are respectively 3, 10 and 2 seconds. The latter are time intervals, not clock times. The clock starts at the beginning of the observation and continues running through the end, and clock times are the times showing on the clock. The clock cannot run backward, so clock times cannot decrease.The midpoint clock times are 3.5 seconds (halfway between clock times 2 and 5 seconds), 10 seconds (halfway between 5 and 15 seconds) and 16 seconds (halfway between 15 and 17 seconds).Half the time intervals would give you 1.5, 5 and 1 second.It should be clear that midpoint clock times cannot decrease, whereas time intervals can either increase or decrease.
&#
** Your table of average velocity of water surface vs. clock time: **
1.79,.50
.030,21.6
.045,17.7
.125,6.8
.280,2.14
.055,14,5
.255,3.13
.175,5.14
.470,1.59
.425,2.11
.400,1.50
** 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 on my y axis start at two and increase in increments of two up to 22 cm/s
My intervals on the x axis, start at 0.1, and increase by .1 up to 1.2.
This graph does not represent a straight line either. The data points seem to be very sporadic and I can't identify a pattern.
** 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: **
1.79,.279
.030,720
.045,393
.125,54.4
.280,7.64
.055,263
.255,12.2
.175,29.3
.470,3.38
.425,4.96
.400,3.75
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
My data is extremely inconclusive. I can't tell a pattern at all.
I think that the acceleration is probably increasing.
You appear to have confused time interval with clock time in your first data report, and it appears this confusion has led to some errors in your analysis. See my notes, let me know if you have questions, and please submit a revision.