course phy121 äźÓšťţš¦»µ”Vá¤Äźč‘ćo•assignment #004
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08:05:03 Intro Prob 6 given init vel, accel, `dt find final vel, dist If initial velocity is v0, acceleration is a and time interval is `dt, then in symbols what are the final velocity vf and the displacement `ds?
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RESPONSE --> vf = v0 + a * 'dt 'ds + v0 'dt + .5a 'dt^2 confidence assessment: 3
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08:06:46 **You would use accel. and `dt to find `dv: a * `dt = `dv. Adding `dv to initial vel. vo you get final vel. Then average initial vel. and final vel. to get ave. vel.: (v0 + vf) / 2 = ave. vel. You would then multiply ave. vel. and `dt together to get the distance. For example if a = 3 m/s^2, `dt = 5 s and v0 = 3 m/s: 3 m/s^2 * 5 s = 15 m/s = `dv 15 m/s + 3 m/s = 18 m/s = fin. vel. (18 m/s + 3 m/s) / 2 = 10.5 m/s = vAve 10.5 m/s * 5 s = 52.5 m = dist. In more abbreviated form: a * `dt = `dv v0 + `dv = vf (vf + v0) /2 = vAve vAve * `dt = `ds so `ds = (vf + v0) / 2 * `dt. **
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RESPONSE --> I forgot to give vAve, but I understand that it is simply the initial velocity + the final velocity, all divided by 2. I answered this question entirely in symbols, because I thought that is what the directions said to do. self critique assessment: 2
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08:07:39 What is the displacement `ds associated with uniform acceleration from velocity v0 to velocity vf in clock time `dt?
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RESPONSE --> 'ds = (v0 + vf) /2 * 'dt confidence assessment: 3
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08:07:55 ** Since accel is uniform vAve = (v0 + vf) / 2. Thus displacement is `ds = vAve * `dt = (v0 + vf) / 2 * `dt, which is the first equation of uniformly accelerated motion. **
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RESPONSE --> ok self critique assessment: 3
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08:09:54 Describe the flow diagram we obtain for the situation in which we know v0, vf and `dt.
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RESPONSE --> First, we use v0 and vf to determine vAve, so there are lines going from v0 and vf that meet at vAve. Using vAve and 'dt, we can determine 'ds, so we draw lines from those to meet at 'ds. confidence assessment: 2
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08:11:12 ** The first level in the diagram would contain `dt, v0 and vf. Then v0 and vf would connect to `dv in the second level. The second level would also contain vAve, connected from vf in the first level to v0 in the first level. The third level would contain an a, connected to `dv in the second level and `dt in the first level. The third level would also contain `ds, connected to vAve in the fourth level and `dt in the first level. **
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RESPONSE --> My diagram was too specific, and did not include 'dv and a. I understand that these are quantities that can be derived from v0, vf, and 'dt as well. self critique assessment: 2
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08:12:12 Query Add any surprises or insights you experienced as a result of this assignment.
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RESPONSE --> Though I understood that not all acceleration is uniform, it was helpful to learn how to determine in which cases it is and is not. confidence assessment: 3
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08:12:58 ** Student Response: I think I really confused what information stood for what in the Force and Pendulum Experiment. However, I enjoy doing the flow diagrams. They make you think in a different way than you are used to. INSTRUCTOR NOTE: These diagrams are valuable for most people. Not all--it depends on learning style--but most. **
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RESPONSE --> I do not like flow diagrams very much, although I can understand how they can be a valuable learning tool. self critique assessment: 2
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