cq_1_161

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

a^2 + b^2 = c^2

5 cm^2 + 8 cm^2 = c^2

c = 9.43 cm

Length of band is 9.43 cm.

9.43 – 7.5 = 1.93

1.93 * .7 Newtons = 1.351 Newtons Tension

#$&*

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

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

9.43 cm North East

#$&*

• What is the magnitude of this vector?

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

9.43 cm

#$&*

• 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: ->->->->->->->->->->->-> :

9.43 cm NE / 9.43 cm = 1 NE

#$&*

• 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 NE * 1 .51 Newtons = 1.351 Newtons NE

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

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

x components = cm East

y components = Newtons North

#$&*

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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45 minutes

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Good work on most parts, but you need to understand the components of the various vectors. The direction is generally around NE, but the result needs to be more specific than that.

&#Please compare your solutions with the expanded discussion at the link

Solution

Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified. &#