Phys 202
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 water flows from the cylinder.
** Is the velocity of the water surface increasing, decreasing, etc.? **
I would expect the velocity of the water surface to 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 exiting water would be decreasing as the water flowed from the cylinder. The diameter of the cylinder would affect the height of the water which would in turn affect the pressure. The diameter of the hole would affect the velocity of the water exiting the cylinder. The velocity at the water surface would be affected by the velocity of the exiting water.
** Explain how we know that a change in velocity implies the action of a force: **
As the depth of a liquid increases the weight of the water above that depth also increases. This creates a larger force at the bottom of the container than at the surface. The velocity increases because of this change in force which is why the water accelerates and leaves the hole faster.
** 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.
** What do you think a graph of depth vs. time would look like? **
I think a graph of depth vs. time would have a negative slope that would become less shallow over time.
** 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 of the stream decreases as time goes on.
** Does this distance change at an increasing, decreasing or steady rate? **
The distance changes at a decreasing rate.
** What do you think a graph of this horizontal distance vs. time would look like? **
I think the graph would have a negative slope and would be decreasing at a decreasing rate.
** The contents of TIMER program as you submitted them: **
1 172.9375 172.9375
2 175.0469 2.109375
3 177.2656 2.21875
4 180.0156 2.75
5 182.6094 2.59375
6 185.625 3.015625
7 188.9375 3.3125
8 192.6094 3.671875
9 197.2969 4.6875
10 203.375 6.078125
11 212.5 9.125
12 215.3281 2.828125
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
3 mm
5 mm
** Your table for depth (in cm) vs clock time (in seconds) **
0, 16.4
2.109375, 15.1
4.328125, 13.6
7.078125, 12.1
9.671875, 10.6
12.6875, 9.1
16, 7.6
19.671875, 6.1
24.359375, 4.6
30.4375, 3.1
39.5625, 1.5
42.390625, 0
** 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 graph has a negative slope that is decreasing at a decreasing rate. It intercepts the y axis at 16.4 cm and the x axis at 42 seconds.
** Your explanation and list of average average velocities: **
I obtained the average velocities by calculating the change in depth in each interval and dividing that by the change in the time interval.
0.62
0.68
0.55
0.58
0.5
0.45
0.41
0.32
0.25
0.18
0.54
** The midpoints of your time intervals and how you obtained them: **
I obtained the clock times at the midpoints of my time intervals my dividing my time intervals in half and adding those to the previous clock time.
1.06
3.22
5.71
8.38
11.18
14.34
17.84
22
27.4
34.96
40.96
** Your table of average velocity of water surface vs. clock time: **
1.06, 0.62
3.22, 0.68
5.71, 0.55
8.38, 0.58
11.18, 0.5
14.34, 0.45
17.84, 0.41
22, 0.32
27.4, 0.25
34.96, 0.18
40.96, 0.54
** Your description of your graph of average velocity vs clock time: **
The graph has a negative slope overall that is decreasing at a decreasing rate. There are some jagged points at the beginning.
** Your explanation of how acceleration values were obtained: **
I obtained acceleration values by taking the change in the average velocities during the time intervals, divided by the change in time over those intervals.
** Your acceleration vs clock time table: **
1.06, 0.58
3.22, 0.028
5.71, 0.52
8.38, 0.011
11.18, 0.029
14.34, 0.016
17.84, 0.011
22, 0.022
27.4, 0.013
34.96, 0.009
40.96, 0.06
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
I think the acceleration is decreasing overall. However there is more uncertainty in the acceleration so it is harder to pick out the trend. I think the acceleration of the water surface is actually decreasing.
** **
1 hour 30 minutes
&#Very good responses. Let me know if you have questions. &#