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course Phy 231

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Assignment 0

course Phy 231

????????·?z????··assignment #001001.

Your work has been received. Please scroll through the document to see any inserted notes (inserted at the appropriate place in the document, in boldface) and a note at the end. The note at the end of the file will confirm that the file has been reviewed; be sure to read that note. If there is no note at the end, notify the instructor through the Submit Work form, and include the date of the posting to your access page.

Physics I

09-15-2007

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11:52:23

Explain in your own words how the standard deviation of a set of numbers is calculuated.

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RESPONSE -->

The standard deviation of a set of numbers is calculated by squaring each number in turn and adding these squares together. The result is then divided by 1 less than the total number of numbers unless it is greater than 30. You then take the square root of that result.

confidence assessment: 3

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12:11:11

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 -->

When you plot graph, unless the data points are stated as they are plotted, they can be open to interpretiation from one observer to the next. For example, if you plotted a point at (7,0) and the axis was marked every 5, if the point was not marked as (7,0), then someone may think that it is 6 or 8, or anywhere in between. This could lead to a quite different slope of the graph than what you plotted initially.

confidence assessment: 3

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12:16:13

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 change in position with respect to time. It is the rate at which position changes.

confidence assessment: 3

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12:16:37

** 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 -->

self critique assessment: 3

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12:17:45

Given average speed and time interval how do you find distance moved?

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RESPONSE -->

The distance is found by multiplying the average velocity by the time interval..

confidence assessment: 3

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12:17:55

** You multiply average speed * time interval to find distance moved.

For example, 50 miles / hour * 3 hours = 150 miles. **

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RESPONSE -->

self critique assessment: 3

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12:21:54

Given average speed and distance moved how do you find the corresponding time interval?

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RESPONSE -->

You can find the time interval by dividing the distance by the average velocity.

For example, the time it takes to travel 25m at an average velocity of 5m/s is:

25m/(5m/s) = 25m*(1s/5m) = 5s

confidence assessment: 3

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12:22:49

** 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 -->

self critique assessment: 3

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12:24:22

Given time interval and distance moved how do you get average speed?

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RESPONSE -->

The average velocity is found by taking the distance traveled and dividing it over the time interval. For example, 25m and 5s would be 25m/5s= 5m/s

confidence assessment: 3

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12:24:30

** 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 -->

self critique assessment: 3

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