#$&*
PHY 201
Your 'cq_1_14.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_14.1_labelMessages **
A rubber band begins exerting a tension force when its length is 8 cm. As it is stretched to a length of 10 cm its tension increases with length, more or less steadily, until at the 10 cm length the tension is 3 Newtons.
• Between the 8 cm and 10 cm length, what are the minimum and maximum tensions, and what do you think is the average tension?
answer/question/discussion: ->->->->->->->->->->->-> :
min - 0 N, max - 3 N, average = 3/2 = 1.5 N
#$&*
• How much work is required to stretch the rubber band from 8 cm to 10 cm?
answer/question/discussion: ->->->->->->->->->->->-> :
1.5 N * 0.02 m = 0.03 J
#$&*
• During the stretching process is the tension force in the direction of motion or opposite to the direction of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
opposite the direction of motion.
#$&*
• Does the tension force therefore do positive or negative work?
answer/question/discussion: ->->->->->->->->->->->-> :
negative
#$&*
The rubber band is released and as it contracts back to its 8 cm length it exerts its tension force on a domino of mass .02 kg, which is initially at rest.
• Again assuming that the tension force is conservative, how much work does the tension force do on the domino?
answer/question/discussion: ->->->->->->->->->->->-> :
0.03 J
#$&*
• 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: ->->->->->->->->->->->-> :
0.03 J
#$&*
• At this point how fast will the domino be moving?
answer/question/discussion: ->->->->->->->->->->->-> :
KE = .5 *m*v^2
0.03 J = .5 * 0.02 kg * v^2
V= +/- 1.73 m/s = + 1.73 m/s
#$&*
*#&!
&#Very good responses. Let me know if you have questions. &#