Assignment 1

course Phy 201

棽㦋ΗpߴI‚assignment #001

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001.

Physics I

05-23-2008

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18:40:38

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

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RESPONSE -->

To find the standard deviation, find the deviations of all the data points from their mean. Then, square these deviations and find the average of that value. Then take the square root of this average, and the obtained value is the standard deviation.

confidence assessment: 3

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18:42:13

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 fitting a straight line to a graph of y vs. x data, you want to get the line that minimizes the distance of each point vertically to the line, without actually going through any of the given points. For any given graph of points, there will be multiple lines that could work for this, and a slightly different slope will yield different y-intercepts.

confidence assessment: 3

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18:43:49

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 measure of a distance traveled divided by the time it took to travel that distance. This is an example of a rate because it breaks down how far an object travels per unit time.

confidence assessment: 3

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18:44:01

** 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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18:44:41

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

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RESPONSE -->

Velocity= distance moved/ time interval.

If you have the velocity and the time interval, you multiply the two together to find the distance moved.

confidence assessment: 3

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18:45:45

** 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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18:48:20

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

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RESPONSE -->

Average speed= distance moved/ time interval

Rearranging this equation to solve for the time interval we get Time interval=Distance traveled/ average speed. Therefore, to find the time interval you divide the distance traveled by the average speed.

confidence assessment: 3

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18:48:29

** 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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18:48:53

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

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RESPONSE -->

Average speed= Distance moved/time interval

confidence assessment: 3

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18:49:01

** 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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