course Phy 231 An automobile traveling a straight line is at point A at clock time t = 9 sec, where it is traveling at 10 m/s, to a certain point B. If the automobile accelerates uniformly at a rate of .9 m/s/s, then if it reaches point B at clock time t = 14 sec:v(initial) = 10 m/sec
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23:00:59 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 --> The final velocity is obtained by calculating the change in velocity and adding that quantity to the initial velocity: a * 'dt = 'dv 'dv + v0 = vf The displacement is obtained by calculating the average velocity and multiplying that quanitity by the change in time: (vf + v0) / 2 = vAve vAve * 'dt = 'ds
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23:01:18 **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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23:04:40 What is the displacement `ds associated with uniform acceleration from velocity v0 to velocity vf in clock time `dt?
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RESPONSE --> The displacement is the product of the average velocity and the time interval: ( vf + v0 ) / 2 * 'dt = 'ds
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23:04:54 ** 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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23:07:15 Describe the flow diagram we obtain for the situation in which we know v0, vf and `dt.
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RESPONSE --> With known quantities of initial and final velocities and the time interval, we calculate the average velocity. We then use the average velocity and time interval to calculate the displacement.
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23:14:12 ** 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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23:17:01 Query Add any surprises or insights you experienced as a result of this assignment.
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RESPONSE --> It's easy to make simple arithmetic errors, but the more problems I do the faster I spot my errors when quantities aren't what I expect.
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23:17:20 ** 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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course Phy 231 An automobile traveling a straight line is at point A at clock time t = 9 sec, where it is traveling at 10 m/s, to a certain point B. If the automobile accelerates uniformly at a rate of .9 m/s/s, then if it reaches point B at clock time t = 14 sec:v(initial) = 10 m/sec
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22:45:07
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RESPONSE -->
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23:00:59 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 --> The final velocity is obtained by calculating the change in velocity and adding that quantity to the initial velocity: a * 'dt = 'dv 'dv + v0 = vf The displacement is obtained by calculating the average velocity and multiplying that quanitity by the change in time: (vf + v0) / 2 = vAve vAve * 'dt = 'ds
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23:01:18 **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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23:04:40 What is the displacement `ds associated with uniform acceleration from velocity v0 to velocity vf in clock time `dt?
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RESPONSE --> The displacement is the product of the average velocity and the time interval: ( vf + v0 ) / 2 * 'dt = 'ds
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23:04:54 ** 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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23:07:15 Describe the flow diagram we obtain for the situation in which we know v0, vf and `dt.
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RESPONSE --> With known quantities of initial and final velocities and the time interval, we calculate the average velocity. We then use the average velocity and time interval to calculate the displacement.
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23:14:12 ** 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 -->
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23:17:01 Query Add any surprises or insights you experienced as a result of this assignment.
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RESPONSE --> It's easy to make simple arithmetic errors, but the more problems I do the faster I spot my errors when quantities aren't what I expect.
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23:17:20 ** 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 -->
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