cq_1_161

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PHY 201

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: ->->->->->->->->->->->-> :

d=’sqrt((10-5)^2 + (17-9)^2) = 9.4 cm

difference = 9.4 cm - 7.5 cm = 1.9 cm

1.9 cm * 0.7 N = 1.3 N

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• What is the vector from the first point to the second?

answer/question/discussion: ->->->->->->->->->->->-> :

1.3N with an angle 58 deg. from horizontal

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• What is the magnitude of this vector?

answer/question/discussion: ->->->->->->->->->->->-> :

1.3 N

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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: ->->->->->->->->->->->-> :

1, v_x = 0.53, v_y = 0.85

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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: ->->->->->->->->->->->-> :

1.3 N

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1.3 N is the magnitude of the vector, but is not the vector.

The vector has magnitude and direction, which can be given explicitly or expressed by giving its x and y components.

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• What are the x and y components of the new vector?

answer/question/discussion: ->->->->->->->->->->->-> :

v_x = 0.69N, v_y = 1.10N

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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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15 minutes

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Good. You have one error, related more to terminology than actual knowledge, but be sure to check my note.

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