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Phy 121
Your 'cq_1_14.1' 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_14.1_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, and what do you think is the average tension?
answer/question/discussion: ->->->->->->->->->->->-> :
min tension=0N
max tension=3N
average tension= (0N+3N)/2
average tension=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: ->->->->->->->->->->->-> :
'ds=2cm
average force=1.5N
dw=1.5N*.02m= 3 J
@&
Good, but 1.5 * .02 = .03, not 3.
*@
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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: ->->->->->->->->->->->-> :
in the direction of motion
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Does the tension force therefore do positive or negative work?
answer/question/discussion: ->->->->->->->->->->->-> :
tension force is does negative 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: ->->->->->->->->->->->-> :
'dw=F*ds= 1.5N*.02m= .03J
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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: ->->->->->->->->->->->-> :
'dwnet='dKE
'dKE= .03J
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At this point how fast will the domino be moving?
answer/question/discussion: ->->->->->->->->->->->-> :
KE=1/2m v^2
vf=sqrt(2*KE/m)
vf=sqrt((2*.03J)/ .02kg)= 1.73 m/s
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** **
25 mins
** **
&#Very good responses. Let me know if you have questions. &#
#$&*
Phy 121
Your 'cq_1_14.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_14.1_labelMessages **
A rubber band begins exerting a tension force when its length is 8 cm. As it is stretched to a length of 10 cm its tension increases
with length, more or less steadily, until at the 10 cm length the tension is 3 Newtons.
Between the 8 cm and 10 cm length, what are the minimum and maximum tensions, and what do you think is the average tension?
answer/question/discussion: ->->->->->->->->->->->-> :
min tension=0N
max tension=3N
average tension= (0N+3N)/2
average tension=1.5 N
#$&*
How much work is required to stretch the rubber band from 8 cm to 10 cm?
answer/question/discussion: ->->->->->->->->->->->-> :
'ds=2cm
average force=1.5N
dw=1.5N*.02m= 3 J
#$&*
During the stretching process is the tension force in the direction of motion or opposite to the direction of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
in the direction of motion
#$&*
Does the tension force therefore do positive or negative work?
answer/question/discussion: ->->->->->->->->->->->-> :
tension force is does negative work
#$&*
The rubber band is released and as it contracts back to its 8 cm length it exerts its tension force on a domino of mass .02 kg,
which is initially at rest.
Again assuming that the tension force is conservative, how much work does the tension force do on the domino?
answer/question/discussion: ->->->->->->->->->->->-> :
'dw=F*ds= 1.5N*.02m= .03J
#$&*
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: ->->->->->->->->->->->-> :
'dwnet='dKE
'dKE= .03J
#$&*
At this point how fast will the domino be moving?
answer/question/discussion: ->->->->->->->->->->->-> :
KE=1/2m v^2
vf=sqrt(2*KE/m)
vf=sqrt((2*.03J)/ .02kg)= 1.73 m/s
#$&*
** **
25 mins
** **
&#Your work looks very good. Let me know if you have any questions. &#