velocity and  rates

course Phy 121

?z??????????assignment #000

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.

000. `Query 0

Physics I

06-13-2007

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13:25:08

The Query program normally asks you questions about assigned problems and class notes, in question-answer-self-critique format. Since Assignments 0 and 1 consist mostly of lab-related activities, most of the questions on these queries will be related to your labs and will be in open-ended in form, without given solutions, and will not require self-critique.

The purpose of this Query is to gauge your understanding of some basic ideas about motion and timing, and some procedures to be used throughout the course in analyzing our observations. Answer these questions to the best of your ability. If you encounter difficulties, the instructor's response to this first Query will be designed to help you clarify anything you don't understand. {}{}Respond by stating the purpose of this first Query, as you currently understand it.

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RESPONSE -->

ok

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assignment #001

001.

Physics I

06-13-2007

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13:28:05

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

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RESPONSE -->

you take the deviations from a certain mean, square those deviations, add them together and divide by one less than how many numbers you added together, and then get the square root of that number. that is the standard deviation

confidence assessment: 3

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13:29:35

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 -->

fitting a straight line to a graph requires getting all points, above and below the line, to equal out.

two people may see the line differently as in our lab exercise, simply because we used visual techniques to ""guess"" about where the line should be

confidence assessment: 3

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13:30:29

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 distance something travels divided by the time it took to get there. it is a rate because the velocity wasn't necessarily the same throughout the entire time of travel

confidence assessment: 3

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13:31:16

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

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RESPONSE -->

you multiply avg speed by the time interval and you get the distance moved

confidence assessment: 3

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13:31:46

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

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RESPONSE -->

you divide distance moved by avg speed to get time interval

confidence assessment: 3

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13:32:16

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

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RESPONSE -->

divide distance moved by time interval to get avg speed

confidence assessment: 3

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assignment #002

002. `Query 2

Physics I

06-13-2007

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16:30:52

** Questions about velocity, average velocity, acceleration, etc. are very confusing because so many of the concepts have similar definitions. People have trouble distinguishing things like average velocity, which for uniform acceleration can be obtained in a process that adds two velocities, from average acceleration, which involves subtracting two velocities; one of these processes involves dividing by 2 and the other dividing by the time interval `dt.

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RESPONSE -->

ok

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16:31:06

It is essential to keep the definitions and the meanings of the terms very clear and to work everything from definitions. It is equally important to have a good common-sense understanding of every definition so you can develop the intuition to make sense of everything you do.

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RESPONSE -->

i agree

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16:31:17

That inevitably takes people a little time. But in the process you develop the habits you will need to succeed in the course. **

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RESPONSE -->

good advice

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16:32:30

How is acceleration an example of a rate of change?

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RESPONSE -->

because vAve = 'dv/`dt

confidence assessment: 2

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16:33:01

If you know average acceleration and time interval what can you find?

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RESPONSE -->

you can find the distance traveled

confidence assessment: 3

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16:34:43

Can you find velocity from average acceleration and time interval?

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RESPONSE -->

no you cannot - you need a reference point

confidence assessment: 2

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16:35:26

Can you find change in velocity from average acceleration and time interval?

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RESPONSE -->

yes you can

confidence assessment: 3

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16:36:20

Can you find average velocity from average acceleration and time interval?

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RESPONSE -->

no you can't, you still need more info

confidence assessment: 3

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16:37:04

You can find only change in velocity from average acceleration and time interval. To find actual velocity you have to know at what velocity you started. Why can't you find average velocity from acceleration and time interval?

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RESPONSE -->

because you need either the starting or ending velocity to figure it out

confidence assessment: 3

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16:40:41

Principles of Physics Students and General College Physics Students: Problem 14. What is your own height in meters and what is your own mass in kg, and how did you determine these?

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RESPONSE -->

i am 1.78meters tall and i weigh 68.2 kg

i simply converted inches (70) to meters

and pounds (150) to kilograms

confidence assessment: 3

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"

Excellent.