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PHY 121
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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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: ->->->->->->->->->->->-> :
I found the length of the rubber band as follows:
a^2 + b^2 = c^2
(10 cm-5 cm)^2 + (17 cm-9 cm)^2 = c^2
(5cm)^2 + (8cm)^2 = c^2
25 cm^2 + 64 cm^2 = c^2
c^2 = 89 cm^2
c = 9.4 cm
Since it doesn't have tension until 7.5 cm, I subtracted 7.5 cm from 9.4 cm to find the difference. 9.4 cm - 7.5 cm = 1.9 cm.
For each cm, it has .7 Newtons of force, so I multiplied .7 N * 1.9, and got 1.33 N
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What is the vector from the first point to the second?
answer/question/discussion: ->->->->->->->->->->->-> :
The vector is 9.4
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What is the magnitude of this vector?
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The magnitude is 9.4
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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: ->->->->->->->->->->->-> :
If I divide the vector by its magnitude, the answer is 1.
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A vector has a magnitude and a direction. You are right about the magnitudes.
What is the direction of your force vector, and what is the direction of this unit vector?
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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?
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When I multiply this vector by the tension per centimeter, I get .7. If I am misinterpreting and I'm supposed to multiply by the tension of this rubberband, then I get 1.33.
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You should multiply by the tension, so the magnitude will be 1.33.
The vector also has a direction, which you must specify.
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What are the x and y components of the new vector?
answer/question/discussion: ->->->->->->->->->->->-> :
I do not know what the x and y components of the new vector would be.
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You need to go back and find the directions of the various vectors.
The directions will be angles as measured counterclockwise from the positive x axis.
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*#&!
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Spend up to 10 minutes working on the questions about angles, and see how much you can get. If you aren't making any progress let me know and I'll provide additional hints.
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