Phys 122
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.? **
decrease
** Is the velocity of the water surface increasing, decreasing, etc.? **
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? **
These are all related because one thing can affect the other: the velocity of the exiting water would be greater if the diameter of the hole was bigger, etc.
One way to determine the velocity of the water surface would be to have a clock and watch the surface as it falls. The velocity could be 10 ml/second.
** Explain how we know that a change in velocity implies the action of a force: **
The change in velocity would make it so there is a action of a force because as the velocity changes, the force is obviously going to change.
** Does the depth seem to be changing at a regular rate, at a faster and faster rate, or at a slower and slower rate **
slower and slower.
** What do you think a graph of depth vs. time would look like? **
It would be a negative correlated line with a slight curve towards the end of the depth. The depth would be decreasing as time increased but would be doing so slower and slower.
** 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? **
Decrease
** Does this distance change at an increasing, decreasing or steady rate? **
decreasing. Because the force of the liquid would be decreasing as more and more liquid left the cylinder.
** What do you think a graph of this horizontal distance vs. time would look like? **
It would have a negative correlated line with a slight curve at the bottom.
** The contents of TIMER program as you submitted them: **
Lap: Time:
1, :02.5
2, :02.0
3, :02.5
4, :02.3
5, :02.6
6, :02.9
7, :03.1
8, :03.7
9, :04.7
10, :05.7
11, :05.7
Total time: 35.7 sec
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
1.25 cm between each mark, 20 cm from outflow tube to 250ml mark.
** Your table for depth (in cm) vs clock time (in seconds) **
Clock Time (seconds): Water Surface(cm):
0 20cm
:02.5 18.75
:04.5 17.5
:07.0 16.25
:09.3 15
:11.9 13.75
:14.8 12.5
:17.9 11.25
:21.6 10
:26.3 8.75
:32.0 7.5
:37.7 6.25
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
slower and slower rate
** Your description of your depth vs. t graph: **
This graph has a negative correlation. The water surface is decreasing as time increases. The steepness of the graph seems to level out towards the end of the line.
** Your explanation and list of average average velocities: **
I obtained the velocities by dividing the descending distance by the clock time. IE: at clock time 2.5 seconds, the descending distance was 7.5cm. At clock time 32.0seconds, the distance was 6.5 cm. My velocity=distance/time
Average velocity is (change in position) / (change in clock time).
There are two intervals that include clock time 32.0 seconds. Both intervals happen to last 5.7 seconds, and on each the change in depth is -1.25 cm. So the average velocity on each is (-1.25 cm) / (5.7 s), or approximately -.2 cm/s.
Velocities in cm/s:
:02.5--.55
:04.5 .54
:07.0 .53
:09.3 .52
:11.9 .52
:14.8 .51
:17.9 .49
:21.6 .46
:26.3 .43
:32.0 .39
:37.7 .37
** The midpoints of your time intervals and how you obtained them: **
Time (s)--Avg Velocity (cm/s)
:03.0--.53
:05.5 .52
:08.1 .52
:10.5 .51
:12.6 .50
:16.4 .50
:19.5 .48
:23.9 .46
:28.7 .41
:34.5 .36
Midpoints look good; average velocities for the intervals aren't calculated correctly.
** Your table of average velocity of water surface vs. clock time: **
Time (s)--Avg Velocity (cm/s)
:03.0--.53
:05.5 .52
:08.1 .52
:10.5 .51
:12.6 .50
:16.4 .50
:19.5 .48
:23.9 .46
:28.7 .41
:34.5 .36
** Your description of your graph of average velocity vs clock time: **
This graph has a negative correlation. The slope of the line is decreasing with time, but is not very steep due to the slight change in velocity.
** Your explanation of how acceleration values were obtained: **
Acc=Change in velocity/change in Time
The change in velocity was the velocity I found for each interval. The change in time is simply that.
Acc Values in order in cm/s:
.45
.44
.43
.42
.41
.41
.39
.34
.31
.31
.29
** Your acceleration vs clock time table: **
:03.0, .45 cm/s
:05.5, .44
:08.1, .43
:10.5, .42
:12.6, .41
:16.4, .41
:19.5, .39
:23.9, .34
:28.7, .31
:34.5, .31
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
Acc is increasing due to the greater gap in values towards the end of the graph. I think it is increasing because as the water got down closer to the spout, it took longer for it to run out.
** **
4 hours and 45 minutes
You didn't calculate your average velocities correctly. This should be fairly easy to correct, according to my note. Otherwise your work looks good.
&#Please see my notes and submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end). &#