ph1 query 1

course Phy 201

6/16 around 5:30

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 calculate the standard deviation you first find the mean of all your numbers or the mean of a set of numbers. You then calculate the difference between all your numbers and the mean of all your numbers or the deviation. You make sure you take the absolute value of the difference between the numbers and the mean. Then, you square all of your deviations to get your squared deviations. You then average this number together to get the ‘average’ squared deviations. You then take the square root of the ‘average ‘ squared deviation to get the standard deviation for a set of numbers.

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:

You try to fit a straight line to the points on a graph by making sure all the points are equidistant from the line. But, the line can be visualized in many different ways to fit the data points by varying the slope or the vertical distance. Therefore, there are a lot of uncertainties when deciding on a best fit line.

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 the average distance traveled over a period of time. Therefore, it is an example of a rate because rate is the change in a variable A over the change of a variable B. Velocity is just the change in the distance traveled over the change in the time.

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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Self-critique (if necessary): T

he only thing different is that I stated distance traveled and not position.

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

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Your solution:

D = VT. You plug in the average speed into V and the time interval into T and multiply those together to find the distance moved.

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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Self-critique (if necessary): OK

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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:

D=VT or T=D/V You divide the distance by the average speed to get the corresponding time interval.

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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Self-critique (if necessary):

I stated the formula as D=VT instead of ds=vAve*’dt

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

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Your solution:

ds=vAve*’dt or ds/’dt = vAve. Divide the distance moved by the time interval to get the average speed.

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. **

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&#Good responses. Let me know if you have questions. &#