course Phy201 I got a ""out of time"" error message at end of this query and had to leave. I hope I completed it all. Please let me know if I did not.
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14:52:27 If, as in the object-down-an-incline experiment, you know the distance an object rolls down an incline and the time required, explain how you will use this information to find the object 's average speed on the incline.
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RESPONSE --> The assignments page tells us to enter assignment 0 but we have already completed this assignment. I believe the instructions should say enter assignment 1, not 0. I will exit and complete assignment 1 instead. confidence assessment: 2
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Zz͒{ՃܱXk assignment #001 001. Physics I 09-04-2007
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14:55:35 Explain in your own words how the standard deviation of a set of numbers is calculuated.
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RESPONSE --> Calculate the mean for all the readings, subtract this from each reading to get the size of the deviation from mean for each reading. Square each of the deviations, total the squared values, and divide by one less than the total number of observations. The resulting ""average of the squared deviations"" is what we call standard deviation confidence assessment: 3
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15:00:43 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 --> The idea is to place a straight line on the graph representing a linear relationship between the two variables that minimizes the distance between the line and the data points. This is usually done mathematically using the ""least squares"" method. But it can also be done visually. This becomes more dificult as the scatter grows. Some people try to adjust the slope to get the best fit while others focus more on shifting the line up or down at the same slope (ie, vary the y intercept). The y intercept can be greatly affected by slope since the slope must be extrapolated to reach the y axis. confidence assessment: 3
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15:03:37 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 the first derivative of the position function. In other words, it is the rate at which position changes. It can most commonly be thought of as speed and is expresed as change in position per unit of time such as miles/hr or Meters/sec confidence assessment: 3
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15:04:07 ** 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 --> I understand self critique assessment: 3
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15:07:08 Given average speed and time interval how do you find distance moved?
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RESPONSE --> Vavg*dt=ds average velocity times change in time equals distance traveled confidence assessment: 3
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15:07:26 ** You multiply average speed * time interval to find distance moved. For example, 50 miles / hour * 3 hours = 150 miles. **
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RESPONSE --> I understand self critique assessment: 3
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15:09:46 Given average speed and distance moved how do you find the corresponding time interval?
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RESPONSE --> dt=ds/Vavg Change in time equals change in position divided by avg velocity confidence assessment: 3
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15:10:21 ** 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 --> I understand self critique assessment: 3
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15:11:52 Given time interval and distance moved how do you get average speed?
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RESPONSE --> Vavg=ds/dt Average velocity equals change in position divided by the change in time confidence assessment: 3
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15:12:13 ** 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 --> I understand self critique assessment: 3
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