phy201
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.
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Seed Question 15
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: ->->->->->->->->->->->-> :
At 8 cm tension is 0N at 10 cm tension is 3N so min = 0N and max = 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: ->->->->->->->->->->->-> :
F= 3N
'ds= 8cm - 10 cm = 2cm
'ds= .02m
Fave= 1.5N
'dw= fnet * 'ds
'dw= 1.5N * .02m
'dw= .03J
The KE is .03J because KE = 'dw
So PE is -.03J Because the tension on the rubber band is 100percent conservative and 'PE is work done against net conservative forces.
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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= .5m V^2
m= 20g
m= 20g * 1kg/1000g = .02kg
KE= .03J
.03J= .5(.02kg) V^2
.03J= .01kg v^2
V^2= 3M^2/s^2
v= 1.7m/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: ->->->->->->->->->->->-> :
F=M*a
F= .02kg *9.8m/s^2
f= .196N
If tension is 100 percent conservative it is positive against negative force of gravity
Fnet= 3N - .196N = 2.804N
'dw= .03J
'dw= fnet * 'ds
.03J= 2.804N * 'ds
'ds= .011 meters
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about 45mins
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&#Your work looks very good. Let me know if you have any questions. &#