course Phy 231
ph1 query 1*********************************************
Question: `qExplain in your own words how the standard deviation of a set of numbers is calculated.
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Your solution:
To find the standard deviation, you must go through a series of calculations. First you must find the mean of the set of numbers. Then you must find the difference between each number and the mean. You square each of these values, and find the mean of these new values. Then you take the square root of this mean, and that gives you the standard deviation.
Confidence Assessment: 3
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Question: 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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Your solution:
To make a best-fit line for a graph, you can use some sort of straight edge to make an imaginary line that you feel best represents the flow of the graph. To then find the slope of this best-fit line, you pick two points on this line. You use these points' x and y coordinates to calculate the rise (change in y) and the run (change in x). The slope is the rise divided by the run. You can then use the slope intercept equation to find the y-intercept. This is done by plugging in the x and y coordinates, along with the slope, into the equation y = mx + b. You then solve for b, which is the y-intercept.
Two people may obtain different results for the slope and the y-intercept, because, after all, the best-fit line is an estimate of the flow of the graph. Also picking points on this line is an estimate. Because it is merely an estimation, slight inaccuracies may occur.
Confidence Assessment: 3
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Question: Briefly state what you think velocity is and how you think it is an example of a rate.
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Your solution: Velocity is distance divided by time. It is a rate because it is the change in distance divided by the change in time. A rate is defined as a ratio between two measurements, which velocity is.
Confidence Assessment: 3
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Given Solution:
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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Question: Given average speed and time interval how do you find distance moved?
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Your solution: You can find the distance moved by multiplying the average speed by the time interval.
Confidence Assessment: 3
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Given Solution:
** You multiply average speed * time interval to find distance moved.
For example, 50 miles / hour * 3 hours = 150 miles. **
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Question: Given average speed and distance moved how do you find the corresponding time interval?
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Your solution: You can find the time interval by dividing the distance moved by the average speed.
Confidence Assessment: 3
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Given Solution:
** 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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Question: Given time interval and distance moved how do you get average speed?
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Your solution: You can find the average speed by dividing the distance by the time.
Confidence Assessment: 3
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Given Solution:
** 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. **
&#This looks good. Let me know if you have any questions. &#