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PHY 241
Your 'cq_1_16.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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Copy the problem below into a text editor or word processor.
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A rubber band has no tension until it reaches a length of 7.5 cm. Beyond that length its tension increases by .7 Newtons for every additional centimeter of length.
• What will be its tension if its endpoints are at the points (5 cm, 9 cm) and (10 cm, 17 cm) as measured on an x-y coordinate system?
answer/question/discussion: ->->->->->->->->->->->-> :
9cm-5cm=4cm Tension =0 N
17cm-10=7cm tension =0N
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The length of the rubber band determines its tension. It doesn't matter what the components of its length are.
You can (and do) easily have a rubber band whose length is greater than the maximum zero-tension length of 7.5 cm but whose components are both less than 7.5 cm.
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• What is the vector from the first point to the second?
answer/question/discussion: ->->->->->->->->->->->-> :
(5,8)
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• What is the magnitude of this vector?
answer/question/discussion: ->->->->->->->->->->->-> :
vector=sqrt(x^2+y^2)= sqrt((10-5)^2+(17-9)^2)=9.43N
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• What vector do you get when you divide this vector by its magnitude? (Specify the x and y components of the resulting vector).
answer/question/discussion: ->->->->->->->->->->->-> :
(0.53,0.848) mag=1.004
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• The new vector should have magnitude 1. When you divide a vector by its magnitude the result is a vector with magnitude 1. We call a vector of magnitude 1 a unit vector. What vector do you get when you multiply this new vector (i.e., the unit vector) by the tension?
answer/question/discussion: ->->->->->->->->->->->-> :
Something must be wrong since my tensions are 0N.
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See my first note.
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• What are the x and y components of the new vector?
answer/question/discussion: ->->->->->->->->->->->-> :
Same problem.
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This new vector is called the tension vector. It is a force vector which represents the tension. A force vector can be specified by its components, or equivalently by its magnitude and direction.
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Good work, except for the questions about tension.
&#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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