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 would expect the rate of flow to decrease as the water flows from the cylinder because there is weight of liquid and less pressure forcing the liquid out of the cylinder.
** Is the velocity of the water surface increasing, decreasing, etc.? **
The velocity would decrease. It is my interpretation that by velocity it is mean the rate of change of position of the buoy as the water level descends. Thus since the rate of flow of water out of the cylinder decreases the level of the water will drop at a slower rate so the velocity will decrease.
** 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 dependent on the velocity of the exciting water which depends on the diameter of the hole, the larger the faster the water exits and vice versa. The larger the diameter of the cylinder the more surface area of the water so the more pressure forcing the water out of the hole.
** Explain how we know that a change in velocity implies the action of a force: **
Unless acted upon an object would remain at a constant velocity for an infinite amount of time, neither increasing or decreasings. So if there is a change if velocity a force must have acted upon that velocity in this case gravity.
** 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 and slower rate. However if the pictures were clearer and taken at a closer position so the levels could be read off the cylinder.
** What do you think a graph of depth vs. time would look like? **
A graph of depth vs time would be decreasing at a decreasing rate with depth on the y axis and time on 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 projection of the stream in the horizontal direction decreases as time goes on.
** Does this distance change at an increasing, decreasing or steady rate? **
This distance changes at an increasing rate.
** What do you think a graph of this horizontal distance vs. time would look like? **
It would have a slope that is decreasing at an increasing rate from left to right with the horizontal distance on the y axis and the time on the x axis.
** The contents of TIMER program as you submitted them: **
1 23.39063 23.39063
2 25.92969 2.539063
3 26.05469 .125 - sticky mouse
4 26.42969 .375 - sticky mouse
5 28.57813 2.148438
6 31.46094 2.882813
7 34.33594 2.875
8 37.83594 3.5
9 41.5 3.664063
10 45.63281 4.132813
11 50.125 4.492188
12 55.75 5.625
13 63.4375 7.6875
14 73.02344 9.585938
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
.6 cm
2.1 cm
3.6 cm
5.1 cm
6.6 cm
8.1 cm
9.6 cm
11.1 cm
12.6 cm
14.1 cm
15.6 cm
17.1 cm
** Your table for depth (in cm) vs clock time (in seconds) **
0, 17.1
2.539, 15.6
5.187, 14.1
8.07, 12.6
10.945, 11.1
14.445, 9.6
18.109, 8.1
22.242, 6.6
26.734, 5.1
32.359, 3.6
40.046, 2.1
49.632, 0.6
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
The data shows that the depth is changing at a slower and slower rate.
** Your description of your depth vs. t graph: **
The graph has the time on the x axis and the water level in centimeters on the y axis. The line of best fit has a negative slope. The slope is m = -3.008. The equation of the line of best fit is
y = -3.008 x + 51.43.68. The y intercept is 51.4368.
** Your explanation and list of average average velocities: **
I found the average velocity for each interval by dividing the change in position by the change in time.
.5908 cm/s
.5784 cm/s
.5576 cm/s
.5482 cm/s
.5192 cm/s
.4970 cm/s
.4721 cm/s
.4489 cm/s
.4172 cm/s
.3746 cm/s
.3324 cm/s
** The midpoints of your time intervals and how you obtained them: **
1.269 s
3.863 s
6.628 s
9.507 s
12.695 s
16.275 s
20.171 s
24.484 s
29.542 s
31.707 s
40.343 s
I found the midpoint by taking the running sum of the intervals however I took .5 of the interval I needed the midpoint for and added to the sum of the intervals before it.
** Your table of average velocity of water surface vs. clock time: **
2.539, .5908 cm/s
5.187, .5784 cm/s
8.07, .5576 cm/s
10.945, .5482 cm/s
14.445, .5192 cm/s
18.109, .4870 cm/s
22.242, .4721 cm/s
26.734, .4489 cm/s
32.359, .4172 cm/s
40.046, .3746 cm/s
49.632, .3324 cm/s
** Your description of your graph of average velocity vs clock time: **
The graph has the velocity on the y axis and the time on the x axis. The slope of the line of best fit is decreasing. The slope is -0.0056 and the y intercept is .6021. So the equation of the line
y = -.0056 x + .6021.
** Your explanation of how acceleration values were obtained: **
ave acceleration is the change in velocity over the change in time.
-.00468 cm/s^2
-.00721 cm/s^2
-.00327 cm/s^2
-.00828 cm/s^2
-.00879 cm/s^2
-.00360 cm/s^2
-.00516 cm/s^2
-.00564 cm/s^2
-.00554 cm/s^2
-.00440 cm/s^2
** Your acceleration vs clock time table: **
1.324 s, -.00468 cm/s^2
4.088 s, -.00721 cm/s^2
6.963 s, -.00327 cm/s^2
10.148 s, -.00828 cm/s^2
13.728 s, -.00879 cm/s^2
17.624 s, -.00360 cm/s^2
21.937 s, -.00516 cm/s^2
26.995 s, -.00564 cm/s^2
33.651 s, -.00554 cm/s^2
42.287 s, -.00440 cm/s^2
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
The acceleration of the water surface is decreasing.
I think it is actually decreasing.
Good work. Your values for the acceleration are not very consistent, due to the 'deterioration of difference quotient' effects. This is to be expected.
If your v vs. t graph is relatively linear, this is a good indication that the acceleration is nearly uniform.
Acceleration should in fact be fairly uniform for this experiment, though it's difficult to get conclusive data with the methods used here.