course phy 201 Ҩdz}assignment #000
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20:08:53 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 --> The purpose of this first Query is to measure my understanding of the basic principles about motion and timing used in the previous lab acitvities.
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20:14:17 If, as in the object-down-an-incline experiment, you know the distance an object rolls down an incline and the time required, explain how you will use this information to find the object 's average speed on the incline.
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RESPONSE --> To find the average speed, you divide the distance the object rolls by the average time requried. confidence assessment: 2
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20:17:19 If an object travels 40 centimeters down an incline in 5 seconds then what is its average velocity on the incline? Explain how your answer is connected to your experience.
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RESPONSE --> V = Distance/Time The average velocity is (40/5=8) 8cm/second. In lab experiment, I found the average velocity of a ball-point pin traveling down a book on an incline. confidence assessment: 2
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20:20:08 If the same object requires 3 second to reach the halfway point, what is its average velocity on the first half of the incline and what is its average velocity on the second half?
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RESPONSE --> The average velocity on the first half of the incline is (20/3=6.6667) 6.7cm/second. The average velocity on the second half of the incline is (20/2=10) 10cm/second. confidence assessment: 2
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20:28:40 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 --> The discrepancies could be explained in part by all of the factors. We already established the TIMER program does not accurately report the time past the hundredth (.01) place. There is a great deal of uncertainty when relying on the precision of human triggering. There will always be at least a slight difference of positioning of the object. And human uncertainty is always a factor when experimenting, especially regarding time. confidence assessment: 2
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20:36:05 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 of the listed factors contribute to the uncertainty in timing a number of trails for the object-down-an-incline lab. The lack of precision of the TIMER program probably contributes the least. The precision of human triggering is a big factor when measuring the uncertainty. The actual differences in the time is probably due to some sort of human error, such as positioning. Human uncertainty is, in my opinion, the biggest contributor to the uncertainty in timing. confidence assessment: 2
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20:43:01 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 --> a. To decrease the uncertainty in the TIMER program, we could approximate and use the digits we are certain are accurate. b. If we wanted the lab to be as accurate as possible, we wouldn't be using human triggering. The timing would be calculated by sensors to be exact. c. To decrease the actual differences in the time required for the object to travel the same distance, conditions must be exactly the same for each trial. d. We could eliminate differences in positioning the object prior to release by measuring the distance from each side. e. Human uncertainty could be eliminated by using some type of sensor to measure the exact time the object reached a specific point at the end of the incline. confidence assessment: 2
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20:47:54 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 --> According to my results, doubling the length of the pendulum will result in about half the frequency. confidence assessment: 2
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20:51:50 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 --> In a graph of y vs. x, x is the independant variable so it is always on the horizontal line, making any point on its axis have a y coordinate of zero. Y is the dependant variable so it will be vertical, making any point on its axis have an x coordinate of zero. confidence assessment: 2
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20:55:08 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 --> If the line or curve representing frequency vs. length goes through the vertical axis, it would mean that the length would have to be negative, which is impossible. confidence assessment: 1
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20:56:57 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 --> If the line or curve representing frequency vs. length goes through the horizontal axis, the frequency would have to have a negative value at some point. confidence assessment: 1
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21:01:17 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 two points are 30cm apart. If the ball travels 6cm every one second, it should pass 30cm in five seconds. confidence assessment: 2
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21:04:22 06-19-2007 21:04:22 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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NOTES -------> average velocity = displacement / time interval vAve = `ds / `dt so... displacement = average velocity * time interval `ds = vAve *`dt
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21:14:14 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 --> When first reading chapter 2, I was unaware of the diference between average speed and average velocity. I realized that I had often interchaged the words, thinking they had the same meaning. I understand that an object's velocity takes into account the direction the object is moving. Velocity is found by subtracting the initial position from the final position and dividing the difference by the time elapsed. Speed is the total distance traveled (disregarding the direction) divided by the time elapsed. confidence assessment: 2
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21:24:18 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 the problems on page 39, I had trouble finding the answer for #14. It would be helpful if the book listed the answers so we could have an idea if we are getting the right answers. I know the formulas to use when calculating the average speed and average velocity, but this problem listed several variables and I wasn't sure if I used them correctly. confidence assessment: 2
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