Assignment 1

course Phy 121

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Using the same type of setup you used for the first object-down-an-incline

lab, if the computer timer indicates that on five trials the times of an

object down an incline are 2.42 sec, 2.56 sec, 2.38 sec, 2.47 sec and

2.31 sec, then to what extent do you think the discrepancies could be

explained by each of thefollowing: {}{}a. The lack of precision of the

TIMER program{}{}b. The uncertain precision of human triggering

(uncertainty associated with an actual human finger on a computer mouse)

{}{}c. Actual differences in the time required for the object to travel the

same distance.{}{}d. Differences in positioningthe object prior to release.

{}{}e. Human uncertainty in observing exactly when the object reached

the end of the incline.

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RESPONSE -->

a. The timmer may not be accurate enough to measure precisly.

b. Triggering the timming devise may be inaccurate due to human error.

confidence assessment: 2

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10:08:19

How much uncertainty do you think each of the following would actually

contribute to the uncertainty in timing a number of trials for the object-

down-an-incline lab? {}{}a. The lack of precision of the TIMER program

{}{}b. The uncertain precision of human triggering (uncertainty associated

bLine$(lineCount) =with an actual human finger on a computer mouse){}{}c.

Actual differences in the time required for the object to travel the same

distance.{}{}d. Differences in positioning the object prior to release.{}{}e.

Human uncertainty in observing exactly when the object reached the end

of the incline.

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RESPONSE -->

All

confidence assessment: 3

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10:12:05

What, if anything, could you do about the uncertainty due to each of the

following? Address each specifically. {}{}a. The lack of precision of the

TIMER program{}{}b. The uncertain precision of human triggering

(uncertainty associated with an actual human finger on a computer mouse)

{}{}c. Actualdifferences in the time required for the object to travel the

same distance.{}{}d. Differences in positioning the object prior to release.

{}{}e. Human uncertainty in observing exactly when the object reached the

end of the incline.

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RESPONSE -->

I think a mechanical devise that releases from a set point, triggered

intrevals and exact stopping point would be more constant then allowing

human error.

confidence assessment: 2

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10:18:21

According to the results of your introductory pendulum experiment, do you

think doubling the length of the pendulum will result in half the frequency

(frequency can be thought of as the number of cycles per minute), more

than half or less than half?

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RESPONSE -->

More than half.

I actully tried to doubled the length from one experament to the next .

confidence assessment: 2

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10:26:52

Note that for a graph of y vs. x, a point on the x axis has y coordinate

zero and a point on the y axis has x coordinate zero. In your own words

explain why this is so.

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RESPONSE -->

To compair the two points they must each share a common coordinate.

0 being the common.

The same could be said using any variable as long as the

variable is the same in both coordinates.

(3,0),(0,3)

(3,1),(1,3)...

confidence assessment: 2

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10:32:22

On a graph of frequency vs. pendulum length (where frequency is on the

vertical axis and length on the horizontal), what would it mean for the

graph to intersect the vertical axis (i.e., what would it mean, in terms of

the pendulum and its behavior, if the line or curve representing frequency

vs. length goes through the vertical axis)? What would this tell you about

the length and frequency of the pendulum?

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RESPONSE -->

Then the pendulum would most likely be stationary.

confidence assessment: 1

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10:41:13

On a graph of frequency vs. pendulum length, what would it mean for the

graph to intersect the horizontal axis (i.e., what would it mean, in terms

of the pendulum and its behavior, if the line or curve representing frequency

vs. length goes through the horizontal axis)? What would this tell you

about the length and frequency of the pendulum?

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RESPONSE -->

I am not sure what the question is asking.

confidence assessment: 0

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10:44:56

If a ball rolls down between two points with an average velocity of

6 cm / sec, and if it takes 5 sec between the points, then how far apart

are the points?

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RESPONSE -->

The ball is rolling at 6 cm /sec then every sec 6 cm is added.

dist = v ' dt

v = 6 cm

v = 6 cm/s, not 6 cm

dt = 5 sec

dist = 30 cm

confidence assessment: 3

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10:46:31

On the average the ball moves 6 centimeters every second, so in 5 seconds

it will move 30 cm. {}{}The formal calculation goes like this: {}{}We know

that vAve = `ds / `dt, where vAve is ave velocity, `ds is displacement and

`dt is the time interval. {}It follows by algebraic rearrangement that

`ds = vAve * `dt.{}We are told that vAve = 6 cm / sec and `dt = 5 sec.

It therefore follows that{}{}`ds = 6 cm / sec * 5 sec = 30 (cm / sec)

* sec = 30 cm.{}{}The details of the algebraic rearrangement are asfollows:

{}{}vAve = `ds / `dt. We multiply both sides of the equation by `dt:{}vAve

* `dt = `ds / `dt * `dt. We simplify to obtain{}vAve * `dt = `ds, which

we then write as{}`ds = vAve *`dt.{}{}Be sure to address anything you do

not fully understand in your self-critique.

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RESPONSE -->

I think I have it.

self critique assessment: 3

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10:57:46

You were asked to read the text and some of the problems at the end of

the section. Tell me about something in the text you understood up to a

point but didn't understand fully. Explain what you did understand, and

ask the best question you can about what you didn't understand.

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RESPONSE -->

I understand converting units and standards.

I did not understand problem 1 (two significant figures of the earths age)

confidence assessment: 1

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11:04:26

Tell me about something in the problems you understand up to a point but

don't fully understand. Explain what you did understand, and ask the best

question you can about what you didn't understand.

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RESPONSE -->

In question 1 is it asking for 14 billion years to be broken down into hours,

minutes,seconds?

I think I understand the years to be 1400000000^10

If the time was converted into sec then the number of sec would be

phanominal considering that there are 86400 seconds in one day.

confidence assessment: 3

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&#Your work looks very good. Let me know if you have any questions. &#