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): **
Hi.
** Is flow rate increasing, decreasing, etc.? **
I would expect rate off flow to decrease as fluid pressure is decreasing in relation to fluid level.
** Is the velocity of the water surface increasing, decreasing, etc.? **
I believe velocity would decrease as the water surface became lower.
** 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? **
Velocity of the water surface for a given cylinder would decrease/increase based on the diameter of the hole. Lager diameter, higher velocity. Smaller diameter, slower velocity of water surface. For a given hole diameter, then the larger the diameter of the cylinder would translate to slower velocity of water surface.
The velocity of the exiting water would increase with a reduction of the diameter of the hole.
** Explain how we know that a change in velocity implies the action of a force: **
Newton's laws of motion: An object that is in motion will not change its velocity (accelerate) until a net force acts upon it.
** 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 rate and this would be confirmed by the fact that the pressure on the water exiting the hole would be decreased
** What do you think a graph of depth vs. time would look like? **
It would be sloping downward and gradually shallowing as it went to the right.
** 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 because the pressure acting on the stream s less.
** Does this distance change at an increasing, decreasing or steady rate? **
I would say it would be fairly steady. It would change linearly with the water level.
** What do you think a graph of this horizontal distance vs. time would look like? **
Decreasing at an increasing rate.
** The contents of TIMER program as you submitted them: **
1 1597.703 1597.703
2 1598.516 .8125
3 1599.672 1.15625
4 1601.297 1.625
5 1602.547 1.25
6 1604.266 1.71875
7 1605.75 1.484375
8 1607.141 1.390625
9 1608.766 1.625
10 1610.578 1.8125
11 1612.031 1.453125
12 1613.734 1.703125
13 1615.5 1.765625
14 1617.375 1.875
15 1619.156 1.78125
16 1621.281 2.125
17 1623.047 1.765625
18 1625.156 2.109375
19 1627.063 1.90625
20 1629.5 2.4375
21 1631.891 2.390625
22 1633.656 1.765625
23 1636.719 3.0625
24 1639.359 2.640625
** The vertical positions of the large marks as you reported them, relative to the center of the outflow hole **
0.3
1.4
2.2
3.1
3.9
4.7
5.5
6.3
7.0
7.7
8.5
9.3
10.1
10.8
11.5
12.3
130
13.8
14.5
15.2
15.9
16.6
17.4
It said from smallest to largest?
The order isn't important on this one.
** Your table for depth (in cm) vs clock time (in seconds) **
0, 17.4
0.8125, 16.6
1.15, 15.9
1.625, 15.2
1.25, 14.5
1.71875, 13.8
1.484375, 13.0
1.390625, 12.3
1.625, 12.3
1.8125, 11.5
1.453125, 10.8
1.703125, 10.1
1.765625, 9.3
1.875, 8.5
1.78125, 7.7
2.125, 7.0
1.765625, 6.3
2.109375, 5.5
1.90625, 4.7
2.4375, 3.9
2.390625, 3.1
1.765625, 2.2
3.0625, 1.4
2.640625, 0.3
Seems I will reverse the numbers now based on the explanation. Also, I have used all large graduations where your example seems more spread out than from my measurements.
This is where the order matters, and you've got it right.
&#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? **
Seems to me, except for some anomalies based on my reaction time, that is most certainly supports my original thoughts that the depth is changing at a slower and slower rate.
** Your description of your depth vs. t graph: **
This graph decreases at a decreasing rate. It starts on the vertical axis at 17.4 and 0 seconds and as the line moves to the right the time elapsed is longer for each marked graduation drop.
Do you have a link from another course you offer that more thoroughly describes the Describing Graphs terminology?
** Your explanation and list of average average velocities: **
.8125 = 0.98 cm/sec
1.15625 = 0.61 cm/sec
1.625 = 0.43 cm/sec
1.25 = 0.56 cm/sec
1.71875 = 0.41 cm/sec
1.484375 = 0.54 cm/sec
1.390625 = 0.50 cm/sec
1.625 = 0.43 cm/sec
1.8125 = 0.44 cm/sec
1.453125 = 0.48 cm/sec
1.703125 = 0.41 cm/sec
1.765625 = 0.45 cm/sec
1.875 = 0.43 cm/sec
1.78125 = 0.44 cm/sec
2.125 = 0.32 cm/sec
1.765625 = 0.39 cm/sec
2.109375 = 0.33 cm/sec
1.90625 = 0.42 cm/sec
2.4375 = 0.33 cm/sec
2.390625 = 0.33 cm/sec
1.765625 = 0.45 cm/sec
3.0625 = 0.26 cm/sec
2.640625 = 0.30 cm/sec
I found avg vel by dividing distance by time elapsed. I. E. 0.8cm / 0.81 would equal .98 cm/sec.
** The midpoints of your time intervals and how you obtained them: **
0.40625
0.578125
0.8125
0.625
0.859375
0.7421875
0.6953125
0.8125
0.90625
0.7265625
0.8515625
0.8828125
0.9375
0.890625
1.0625
0.8825125
1.0546875
0.953125
1.21875
1.1953125
0.8828125
1.53125
1.3203125
&#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. &#
Obtained by dividing time interval by 2.
** Your table of average velocity of water surface vs. clock time: **
0.40625, 0.98
0.578125, 0.61
0.8125, 0.43
0.625, 0.56
0.859375, 0.41
0.7421875, 0.54
0.6953125, 0.50
0.8125, 0.43
0.90625, 0.44
0.7265625, 0.48
0.8515625, 0.41
0.8828125, 0.45
0.9375, 0.43
0.890625, 0.44
1.0625, 0.32
0.8825125, 0.39
1.0546875, 0.33
0.953125, 0.42
1.21875, 0.33
1.1953125, 0.33
0.8828125, 0.45
1.53125, 0.26
1.3203125, 0.30
** Your description of your graph of average velocity vs clock time: **
You are going to need to revise your description once you have the correct midpoint clock times.
Decreasing at a increasing rate.
** Your explanation of how acceleration values were obtained: **
0.4 cm/sec
0.93
1.88
1.11
0.20
1.37
1.38
1.88
1.86
1.5
1.77
1.95
2.16
2.02
3.31
2.25
3.19
2.26
3.67
3.61
1.95
5.88
4.40
Avg accell = delta v / delta t
** Your acceleration vs clock time table: **
0.40625, 0.40 cm sec avg accel
0.578125, 0.93
0.8125, 1.88
0.625, 1.11
0.859375, 0.20
0.7421875, 1.37
0.6953125, 1.38
0.8125, 1.88
0.90625, 1.86
0.7265625, 1.5
0.8515625, 1.77
0.8828125, 1.95
0.9375, 2.16
0.890625, 2.02
1.0625, 3.31
0.8825125, 2.25
1.0546875, 3.19
0.953125, 2.26
1.21875, 3.67
1.1953125, 3.61
0.8828125, 1.95
1.53125, 5.88
1.3203125, 4.40
again this will have to be modified when you modify your vel vs. midpoint clock time information.
** According to the evidence here, is acceleration increasing, decreasing, staying the same or is in not possible to tell? **
My result would lead between decreasing to inconclusive. There are, based on my human fallibility, some times that do not seem to correlate with a linear progression of readings. I believe that the acceleration is decreasing.
Good data, but you misinterpreted the meanings of 'clock time' and 'midpoint clock time'. You'll need to revise your work from that point on. /h3>