course PHY 231 Mpn~assignment #001
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04:21:32 Explain in your own words how the standard deviation of a set of numbers is calculuated.
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RESPONSE --> First calculate a mean average. Every deviation is the difference between that actual value and the mean. Take the sum of the deviations. Then divide by that many minus 1. Take the square root of that answer. The standard deviation is the mean + or - that calculation. confidence assessment: 3
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04:22:55 Explain in your own words the process of fitting a straight line to a graph of y vs. x data, and briefly discuss the nature of the uncertainties encountered in the process. For example, you might address the question of how two different people, given the same graph, might obtain different results for the slope and the vertical intercept.
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RESPONSE --> Different results will happen when a string is measured by who observes it. Fitting a best-fit line is by trying not to go through any of the points on the graph unless there is no other way. The ideal way is to go between all of the points. confidence assessment: 1
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04:23:55 Briefly state what you think velocity is and how you think it is an example of a rate.
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RESPONSE --> Velocity is a vector quantity. It is ideally speed with direction. Velocity is distance over a time. Velocity is a rate of distance and time. confidence assessment: 3
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04:24:25 ** A rate is a change in something divided by a change in something else. This question concerns velocity, which is the rate of change of position: change in position divided by change in clock time. **
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RESPONSE --> ok. Average velocity is a rate of change of distance over a change in time. self critique assessment: 2
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04:24:54 Given average speed and time interval how do you find distance moved?
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RESPONSE --> d = v x t distance = velocity x time confidence assessment: 3
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04:25:03 ** You multiply average speed * time interval to find distance moved. For example, 50 miles / hour * 3 hours = 150 miles. **
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RESPONSE --> ok self critique assessment: 3
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04:25:37 Given average speed and distance moved how do you find the corresponding time interval?
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RESPONSE --> d = v x t That means that time equals distance divided by velocity. confidence assessment: 3
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04:25:42 ** time interval = distance / average speed. For example if we travel 100 miles at 50 mph it takes 2 hours--we divide the distance by the speed. In symbols, if `ds = vAve * `dt then `dt = `ds/vAve. Also note that (cm/s ) / s = cm/s^2, not sec, whereas cm / (cm/s) = cm * s / cm = s, as appropriate in a calculation of `dt. **
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RESPONSE --> ok self critique assessment: 3
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04:26:24 Given time interval and distance moved how do you get average speed?
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RESPONSE --> Average speed is calculated by dividing the rate change in distance by the rate change in time. V = delta d / delta t confidence assessment: 3
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04:26:29 ** Average speed = distance / change in clock time. This is the definition of average speed. For example if we travel 300 miles in 5 hours we have been traveling at an average speed of 300 miles / 5 hours = 60 miles / hour. **
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RESPONSE --> ok self critique assessment: 3
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