Phy 231
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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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: ->->->->->->->->->->->-> :
F = kx
3 = k*.1
That would be 3 N = k * .02 m, or 3 N = k * 2 cm.
k = 30
see above, and note that k has units
F = kx
F = 30*.08
F = 2.4
The max tension is given at 3N, the minimum tension is 2.4N.
• 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: ->->->->->->->->->->->-> :
If the system is conservative, the potential energy would be equal to the total work done. Calculating the total work, we get W = F*d = 3*10 = 30J. That means the elastic potential energy would be 30J at 10cm.
• 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: ->->->->->->->->->->->-> :
K = 1/2 mv^2
30J = 1/2 * .02 v^2
30 = .01v^2
3000 = v^2
v = 54.77 m/s
• If instead the rubber band is used to 'shoot' the domino straight upward, then how high will it rise?
answer/question/discussion: ->->->->->->->->->->->-> :
F = ma
3 = .02*a
a = 150
U = mgh
30J = .02*150*h
30 = 3h
h = 10 m
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20 min
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I forgot that the Seed Question had its own submit page so I accidentally submitted it in the Submit Work Form as well.
You're applying the right formulas, but you're not being careful enough with your units.
I recommend that this be reasoned out at a lower level, closer to the definitions, then reconciled with the formulas.
&#Please compare your solutions with the expanded discussion at the link
Solution
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