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Phy 201
Your 'cq_1_19.3' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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Seed Question 19-3
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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An object moving in the direction 120 degrees (as measured counterclockwise to the positive x axis) encounters a net force whose direction is 270 degrees.
Sketch the force and its component along the line of motion, as well as its component perpendicular to the line of motion.
answer/question/discussion: ->->->->->->->->->->->-> :
Once again, I am a little confused on exactly what you want. I drew the vector at 120deg and the net force vector at 270deg. You asked me to sketch the force and its component along the line of motion. Are you referring to the net force at 270deg? Im also not sure what you mean by its component along the line of motion. Im sure this is something simple, I just dont understand what you are asking for.
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Sketch (as you may have already done) the force vector and the velocity vector both originating from the same point. You might, for example, have them both originate from the origin of an x-y coordinate system.
On your sketch, lightly extend the line of your velocity vector both forward and backward.
Now from the tip of your force vector sketch a dotted line to the line of your velocity vector, with your dotted line perpendicular to that line. This dotted line is your projection line, the line that projects your force vector onto the line of your velocity vector.
Sketch a vector which starts at the common initial point of your velocity and force vectors, and ends at the point where the projection line met the line of the velocity vector.
This vector is the component of the force vector along the line of the velocity vector. This component will be shorter than the force vector. It tells you how much effect the force has in this direction.
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Suppose you are facing in the direction of motion. Do you perceive the component of the force along the line of motion to be forward or backward? It this component in the direction of motion or opposite to the direction of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
I am still not clear on this but I will give it my best guess.
Backwards because it is moving to the left. In the direction of the motion.
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Will the object speed up, slow down or maintain a constant speed?
answer/question/discussion: ->->->->->->->->->->->-> :
The object will maintain a constant speed
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If the component of the force vector along the line of the velocity is 'backwards', i.e., in the direction opposite the velocity, then the force will tend to slow the object. The acceleration of the object in this direction is equal to the component of the force in this direction, divided by the mass of the object.
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If you are facing in the direction of motion, then the line perpendicular to the direction of motion will run to your right and to your left. Is the component of the force perpendicular to the line of motion directed to the right or to the left?
answer/question/discussion: ->->->->->->->->->->->-> :
Now I am really confused.
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Will the object veer to the right, to the left or maintain straight-line motion?
answer/question/discussion: ->->->->->->->->->->->-> :
I dont have any kind of a visual to work with in my head or on paper. I have read it and read it again. Hopefully you can explain this so I can understand it a little better.
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Which is greater in magnitude, the component of the force along the line of motion or the component perpendicular to the line of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
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See if you can follow my instructions to sketch the desired component of the vector. I'll be able to tell by your answers whether you have the picture.
If not, let me know and we'll try another approach.
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