Phy231
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.
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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.
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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: min tension 0newton max tension 3newtons
avg tension (0N + 3N)/2=1.5N
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How much work is required to stretch the rubber band from 8 cm to 10 cm?
answer/question/discussion:
'dWnet=Fnet*'ds=1.5N*2cm=3J
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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 to the direction of motion because it is fighting against being stretched.
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Does the tension force therefore do positive or negative work?
answer/question/discussion:
Negative work
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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.
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Again assuming that the tension force is conservative, how much work does the tension
force do on the domino?
answer/question/discussion:
'ds=2cm v0=0m/s
1.5N*2cm=3J
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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:
3J
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At this point how fast will the domino be moving?
answer/question/discussion:
vf=+-'sqrt(2KEf/m)=+-'sqrt(2*3J/.02kg)=+-'sqrt(250m^2/s^2)=+-15.81m/s
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20min
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5/1/10 2pm
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