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phy121
Your 'cq_1_15.1' 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_15.1_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?
answer/question/discussion: ->->->->->->->->->->->-> :
The minimum tension would be 0N and the maximum would be 3N.
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• Assuming that the tension in the rubber band is 100% conservative (which is not actually the case) what is its elastic potential energy at the 10 cm length?
answer/question/discussion: ->->->->->->->->->->->-> :
since it is conservative, this means it is reversible. Therefore:
PE= W
PE= (0N+3N)/2
PE= 1.5N
It would take 0.03J to stretch the band, which means the elastic PE is equal to 0.03J at 10cm.
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• If all this potential energy is transferred to the kinetic energy of an initially stationary 20 gram domino, what will be the velocity of the domino?
answer/question/discussion: ->->->->->->->->->->->-> :
KE= 0.5*m*v^2
0.03J= 0.5*0.02kg*v^2
3m^2/s^2= v^2
V= sqrt(3m^2/s^2)
V= 1.73m/s
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• If instead the rubber band is used to 'shoot' the domino straight upward, then how high will it rise?
answer/question/discussion: ->->->->->->->->->->->-> :
at 0m/s it will be at the highest point,
0.02kg*9.8m/s^2= 0.196N
0.03J= 0.196N*’dy
‘dy= 0.15m
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For University Physics students:
Why does it make sense to say that the PE change is equal to the integral of the force vs. position function over an appropriate interval, and what is the appropriate interval?
answer/question/discussion: ->->->->->->->->->->->-> :
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*#&!
&#Your work looks very good. Let me know if you have any questions. &#