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PHY 241
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: ->->->->->->->->->->->-> :
T increases steadily with length on the interval from T_min = 0 to T_max = 3. TAve = (T_f + T_0) / 2 = 3 / 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: ->->->->->->->->->->->-> :
`dWnet = F_net * `ds = TAve * `ds = 1.5 N * .02 m = .03 J
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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: ->->->->->->->->->->->-> :
Tension force is in the opposite of the direction of motion, trying to pull the stretching end(s) back to the original position(s).
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Does the tension force therefore do positive or negative work?
answer/question/discussion: ->->->->->->->->->->->-> :
Tension does positive work on its surroundings, negative work on the system
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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: ->->->->->->->->->->->-> :
TAve = 1.5 N
`dW_T = TAve * `ds = 1.5 * .02 = .03 J
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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: ->->->->->->->->->->->-> :
`dKE = `dWnet = `dW_T = .03 J
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At this point how fast will the domino be moving?
answer/question/discussion: ->->->->->->->->->->->-> :
`dKE = .03 = (.5)(.02)(v_f^2)
v_f = 1.7 m/s
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*#&!
&#Very good responses. Let me know if you have questions. &#