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): **
Good Evening
** Is flow rate increasing, decreasing, etc.? **
I would expect the rate of flow to decrease as a result of the volume of liquid being reduced. Subsequently reducing the weight of the liquid mass (soda) creating the flow; the force being applied on the liquid leaving the cylinder would decrease respectively, thus creating a reduction in the rate of flow.
** Is the velocity of the water surface increasing, decreasing, etc.? **
Based on my aforementioned solution of the problem, I would expect the buoy's velocity to decrease as it descends. Although the change in velocity may not be discernable.
** 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 should be proportional to the velocity of the exiting water. As the surface velocity decreases, so should the velocity of the exiting water. The diameter of the cylinder should directly effect the mass and weight of the water; thus the diameter of the cylinder will also effect the velocity of the water surface as well as the velocity of the exiting water. As the mass decreased; so should the surface and exiting velocity. Finally the diameter of the hole should directly effect the velocity of the surface and exiting water. A larger hole will allow the mass to decrease much more rapidly; thus velocities would increase proportionally.
** Explain how we know that a change in velocity implies the action of a force: **
In order for the water to have a change in velocity (from rest); a force must be applied to the liquid. That force is the mass of the liquid itself x the force of gravity. As the volume of the liquid is decreased; so is the amount of force that is applied; resulting in a decrease in velocity.
** Does the depth seem to be changing at a regular rate, at a faster and faster rate, or at a slower and slower rate **
Compressive due it it weight x gravity.
It would appear to be changing at a slower and slower rate.
** What do you think a graph of depth vs. time would look like? **
It would be a decreasing arc; starting steep, and flattening out towards horizontal as it approaches the end.
** 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? **
Decreases
** Does this distance change at an increasing, decreasing or steady rate? **
Increasing
** What do you think a graph of this horizontal distance vs. time would look like? **
It would be a decreasing arc; starting regular and flat to horizontal, and increasing in steepness as it approaches the end.
** The contents of TIMER program as you submitted them: **
1 209.5313 209.5313
2 211.9375 2.40625
3 214.6484 2.710938
4 217.4219 2.773438
5 220.4531 3.03125
6 223.5313 3.078125
7 227.0234 3.492188
8 230.7422 3.71875
9 235.1406 4.398438
10 240.8438 5.703125
11 248.0938 7.25
12 253.4844 5.390625
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
.8cm
2.4cm
4.0cm
5.6cm
7.1cm
8.6cm
10.1cm
11.6cm
13.1cm
14.6cm
16.0cm
17.5cm
** Your table for depth (in cm) vs clock time (in seconds) **
0,17.5
2.40,16
2.71, 14.6
2.77, 13.1
3.03, 11.6
3.07, 10.1
3.49, 8.6
3.71, 7.1
4.39, 5.6
5.70, 4.0
7.25, 2.4
5.39, .8
&#It appears you have reported time intervals rather than clock times.
A time interval is the time between two subsequent clicks; a clock time is the running time from the beginning of the experiment.
For example if a series of events occurs at clock times t = 2, 5, 9 and 18 seconds, then the time intervals between these events are 3, 4 and 9 seconds. If the time intervals between a series of four events were 7, 5 and 4 seconds, then if the clock started with the first event the clock times would be 0, 7, 12 and 16 seconds.
Be sure you understand the difference between clock time and time interval. &#
** Is the depth changing at a regular rate, at a faster and faster rate, or at a slower and slower rate? **
The data Supports my answers
The depth changes at a slower and slower rate as the mass of the liquid is reduced.
** Your description of your depth vs. t graph: **
The graph is a descending arc; starting out horizontal flat to increasing in magnitude to a steep arc then returning to a flat to horizontal arc towards its end.
** Your explanation and list of average average velocities: **
Change in distance per interval divided by the Change in time per interval; yields the change in distance per second, for each interval.
.625 cm/s
.553 cm/s
.541 cm/s
.495 cm/s
.488 cm/s
.429 cm/s
.404 cm/s
.341 cm/s
.263 cm/s
.206 cm/s
.278 cm/s
** The midpoints of your time intervals and how you obtained them: **
I obtained them by taking half of the time interval, and added this amount to the preceding clock time. The solutions are as follows;
210.73
213.25
215.98
218.91
221.93
225.24
229.55
232.84
237.99
244.42
250.78
** Your table of average velocity of water surface vs. clock time: **
210.73, .625 cm/s
213.25, .553 cm/s
215.98, .541 cm/s
218.91, .495 cm/s
221.93, .488 cm/s
225.24, .429 cm/s
229.55, .404 cm/s
232.84, .341 cm/s
237.99, .263 cm/s
244.42, .206 cm/s
250.78, .278 cm/s
** Your description of your graph of average velocity vs clock time: **
** Your explanation of how acceleration values were obtained: **
Utilizing the formula for average acceleration.
a average = (V2-V1)/(t2-t1) = cm/s2
-.28 cm/s2
-.0043 cm/s2
-.015 cm/s2
-.0023 cm/s2
-.0178 cm/s2
-.0058 cm/s2
-.019 cm/s2
-.015 cm/s2
-.0088 cm/s2
.0113 cm/s2
** Your acceleration vs clock time table: **
-.28, 210.73
-.0043, 213.25
-.015, 215.98
-.0023, 218.91
-.0178,221.93
-.0058, 225.24
-.019,229.55
-.015, 232.84
-.0088, 237.99
.0113, 244.42
This is clock time vs. acceleration; you've got the columns reversed. Be sure you understand that y vs. x has x in the first column and y in the second.
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
Decreasing
Decreasing
You had some confusion between time intervals and clock times, and your reported midpoint clock times were not consistent with a clock which started at 0 when the water was released.
However these errors didn't cause any errors in the key calculations; you did correctly calculate average velocities and accelerations. So you got good results.