PHY 201
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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, and what do you think is the average tension?
answer/question/discussion: ->->->->->->->->->->->-> :
We know the at the 10 cm length the tension is 3 Newtons, so we know that the tension has to be less than 3 newtons, then the maximum is 3 Newtons. Well, the minimum tension has to be 0 N, because it starts at the 8 cm mark. So, the average tension is 1.5 N.
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• How much work is required to stretch the rubber band from 8 cm to 10 cm?
answer/question/discussion: ->->->->->->->->->->->-> :
If I takes 3 Newtons to stretch the rubber band 2 cm, then the work is represented in Joules. The work done to stretch the rubber band is work done on the system, but I am not sure how to get the joules of work.
to get the work you multiply average force by displacement
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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: ->->->->->->->->->->->-> :
I think that the tension is going in the direction of motion.
you need to describe the direction of the displacement, and the direction of the tension force
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• Does the tension force therefore do positive or negative work?
answer/question/discussion: ->->->->->->->->->->->-> :
The tension therefore does positive 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.
• Again assuming that the tension force is conservative, how much work does the tension force do on the domino?
answer/question/discussion: ->->->->->->->->->->->-> :
Since, the force is conservative; I am sure how to get the work done on the domino.
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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: ->->->->->->->->->->->-> :
The KE is equal to the net work done on the system, which I am not sure how to get it, because I need the data from the earlier questions.
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• At this point how fast will the domino be moving?
answer/question/discussion: ->->->->->->->->->->->-> :
I do not understand this tension part. How do you get the information you need to get the answers from the given variables????
you know that tension changes from 0 N to 3 N in the 2-cm interval, and as you have stated the average tension is 1.5 N.
If you combine this with the definition of work, you can answer most of these questions.
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45 minutes
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&#Very good responses. Let me know if you have questions. &#