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Phy 201
Your 'cq_1_14.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_14.1_labelMessages **
A rubber band begins exerting a tension force when its length is 8 cm. As it is stretched to a length of 10 cm its tension increases with length, more or less steadily, until at the 10 cm length the tension is 3 Newtons.
Between the 8 cm and 10 cm length, what are the minimum and maximum tensions, and what do you think is the average tension?
answer/question/discussion: ->->->->->->->->->->->-> :
0 N at 8 cm to 3 N at 10 cm
atension= (0 N + 3 N) / 2 = 1.5 N
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How much work is required to stretch the rubber band from 8 cm to 10 cm?
answer/question/discussion: ->->->->->->->->->->->-> :
'ds=10 cm - 8 cm = 2 cm.
aForce= (0 N + 3 N) / 2 = 1.5 N.
work exerted on rubber band = aforce * 'ds= 1.5 N * 2 cm = 3.0 N * cm or .03J
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During the stretching process is the tension force in the direction of motion or opposite to the direction of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
Opposite direction
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Does the tension force therefore do positive or negative work?
answer/question/discussion: ->->->->->->->->->->->-> :
It does negative work on motion.
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The rubber band is released and as it contracts back to its 8 cm length it exerts its tension force on a domino of mass .02 kg, which is initially at rest.
Again assuming that the tension force is conservative, how much work does the tension force do on the domino?
answer/question/discussion: ->->->->->->->->->->->-> :
.03J
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Assuming this is the only force acting on the domino, what will then be its kinetic energy when the rubber band reaches its 8 cm length?
answer/question/discussion: ->->->->->->->->->->->-> :
`dW_net = `dKE
`dW_net= +.03 J, `dKE = +.03 J
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At this point how fast will the domino be moving?
answer/question/discussion: ->->->->->->->->->->->-> :
KE = 1/2 m v^2
v = sqrt(2 * KE / m)
v = sqrt( 2 * .03 Joules / (.02 kg) )
v= sqrt(3 m^2 / s^2)
v= 1.7 m/s
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[ extended discussion of T vs. L and T vs. x including graphs at linked document to be provided ]
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&#This looks very good. Let me know if you have any questions. &#