cq_1_011

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Phy 201

Your 'cq_1_01.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** CQ_1_01.1_labelMessages **

The purpose and the process of answering 'seed' questions:

In cloud seeding small crystalline particles (the 'seeds') are scattered throughout a cloud, so that water vapor in the cloud will build up on the 'seed' and eventually fall in the form of rain.

These questions are posed without any previous explanation. You are expected to use what you already know, along with common sense, to answer the questions. It is standard practice in many courses to an instructor to give explanations and examples before asking students to answer questions, and you will see plenty of examples and explanations in this course. However the goal here is to first experience and think about a situation. Whether you think correctly or incorrectly, your thinking gets you started on an idea and forms a 'seed' on which understanding can accumulate.

• You are expected to answer it to the best of your ability, based on what you know at the beginning of this assignment.

• You are not expected to research this question until after you have submitted your best response.

• You are not penalized based on whether your answer is 'right' or 'wrong', but you are expected to think as clearly and deeply as you can about the question.

• You are not, however, expected to spend hours thinking about the question or agonize unduly about your answers. A rule of thumb is to give it up to 20 minutes, half for thinking and half for typing in your answers (maybe a little more for the typing if you don't have good keyboard skills).

• Your answers should consist of your best attempt at a solution, and/or one or more questions about the situation.

• If you think you know the answer or can make a reasonable attempt to answer, then give your answer along with a concise outline of your reasoning.

• If you aren't sure what the question is asking, make your best attempt to interpret and answer it, and consider including one or more questions.

• If you are very sure you don't know what the question is asking, then break it down phrase-by-phrase or even word-by-word and explain what you think each key phrase or word might mean.

• A question consists of a complete but concise statement of what you do and do not understand about the situation.

• There are two ways you can spend an excessive amount of time explaining your solutions and/or asking questions. One is to type a lot more than what is necessary, and another is to spend a lot of time worrying about what is and is not necessary. Balance the two in the way that works best for you.

• Remember that the 'concise' part is more for your benefit than mine. I can read a lot more quickly than you can type, and don't mind reading through a lot of words to understand your meaning.

• You are invited but not required to include comments and/or discussion.

• You are welcome to use reasonable abbreviations in your work.

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Copy the problem below into a text editor or word processor.

• This form accepts only text so a text editor such as Notepad is fine.

• You might prefer for your own reasons to use a word processor (for example the formatting features might help you organize your answer and explanations), but note that formatting will be lost when you submit your work through the form.

• If you use a word processor avoid using special characters or symbols, which would require more of your time to create and will not be represented correctly by the form.

• As you will see within the first few assignments, there is an easily-learned keyboard-based shorthand that doesn't look quite as pretty as word-processor symbols, but which gets the job done much more efficiently.

You should enter your answers using the text editor or word processor. You will then copy-and-paste it into the box below, and submit.

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The problem:

Here is the definition of rate of change of one quantity with respect to another:

The average rate of change of A with respect to B on an interval is

• average rate of change of A with respect to B = (change in A) / (change in B)

Apply the above definition of average rate of change of A with respect to B to each of the following. Be sure to identify the quantity A, thequantity B and the requested average rate.

• If the position of a ball rolling along a track changes from 10 cm to 20 cm while the clock time changes from 4 seconds to 9 seconds, what is the average rate of change of its position with respect to clock time during this interval?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

20-10 = 10

9-4 = 5

10 / 5 = 2 cm/ second is the average rate of change

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Good, but:

``10 / 5 = 2. 10/5 does not equal 2 cm/sec.20 cm - 10 cm = 10 cm, and 9 sec - 4 sec = 5 sec.10 cm / (5 sec) = 2 cm / sec.Units need to be used with every quantity that has units, at every step of a solution. This is very helpful in guarding against common errors. It also helps keep you thinking about the meaning to each calculation, which is valuable when solving an involved problem.

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• If the velocity of a ball rolling along a track changes from 10 cm / second to 40 cm / second during an interval during which the clock time changes by 3 seconds, then what is the average rate of change of its velocity with respect to clock time during this interval?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

40-10= 30

30 / 3= 10cm/ second is the average change of its velocity

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``The units of your calculation are not correct.The units associated with the calculation 40 - 10 are not cm. It they were then, because the units of the denominator are seconds, the units would come out cm/sec. However that is not the case here.Please correct the units of your calculation. The units need to be used throughout the calculation, at every step.

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• If the average rate at which position changes with respect to clock time is 5 cm / second, and if the clock time changes by 10 seconds, by how much does the position change?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

5 * 10 = 50

50cm

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5 * 10 = 50, but 5 * 10 is not equal to 50 cm.

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• You will be expected hereafter to know and apply, in a variety of contexts, the definition given in this question. You need to know this definition word for word. If you try to apply the definition without using all the words it is going to cost you time and it will very likely diminish your performance. Briefly explain how you will ensure that you remember this definition.

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

I always find that the best way to remember something is through repetition. I will ensure that I remember this definition by using it over and over and rewriting to try and ensure it is memorized.

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• You are asked in this exercise to apply the definition, and given a general procedure for doing so. Briefly outline the procedure for applying this definition, and briefly explain how you will remember to apply this procedure.

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

you must always remember that the change in the objects is the most important part. Then you must compare the change in one object compared to the change in another. That way you will remember that the average rate of change in A in respect to B is = (change in A) / (change in B)

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You are doing an excellent job of applying the definitions.

However you need to express every quantity that has units with its units, at every step of every calculation.

You should find it quick and easy to make the necessary modifications.

&#Please see my notes and submit a copy of this document with revisions, comments and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).

Be sure to include the entire document, including my notes.

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