Phy 121
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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: ->->->->->->->->->->->-> :
The minimum and maximum tensions should be equal to each other since the rubberband is not pushing on anything. The band is only pulling against itself. So our maximum and minimum tension is 3 Newtons.
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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: ->->->->->->->->->->->-> :
I think we will need to use the formula .5*k*x^2 to solve for the elastic potential energy. What I’m not sure of is how we would solve this because I’m not sure what value should be used for K and what value should be used for X. I assume that one value would be 3 Newtons and the other would be 2 cm to represent the change in velocity. If we were to solve for this it would give us .5 * 3 Newtons * 2cm^2.
=.5 * 3 Newtons * 4 cm
= 6 Joules
N * cm doesn't give you Joules.
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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: ->->->->->->->->->->->-> :
I would assume that the kinetic energy would be -6 Joules. To solve for the velocity of the domino, I took ½ 10 g * 10 cm= 10.0 Joules
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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: ->->->->->->->->->->->-> :
If the rubberband is used to shoot the domino upward then it will rise to a height of 2 cm. I think that it will be this height because the same amount of kinetic energy to move the object horizontally is the same amount needed to move the object vertically. So if our band is stretched 2cm then it will move 2 cm upward. Part of me also thinks that the object could move higher than that though.
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35 m
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This is a resubmission. I did not copy and paste the correct info the first time.
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Solution
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