Your 'cq_1_20.1' 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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Assignment 20 Seed Question 1
The situation here is similar to that depicted above, though the distances of the rubber bands from the center are different. The die on which the strap rotates is not visible, but is attached to the tabletop; the blue push pin constrains the system to rotate about a vertical axis through the center of the die.
The problem:
The metal strap used in the Angular Velocity of a Strap experiment is constrained by a vertical push pin to rotate about a hole in a die. The die is glued in place to a massive tabletop. A rubber band is attached to a point 15 cm from the axis and stretched so that it exerts a force of 3 Newtons, directed perpendicular to the rod. If this force is unopposed it will accelerate the system rapidly. You want to attach a second rubber band 5 cm from the axis to prevent the system from rotating.
• How much force will that rubber band have to exert?
answer/question/discussion: The rubber band needs to exert a force of 9 N. This was found by seeting the two rubber bands impact equal to each other in order to get the metal rod not to move. Thus, 5cm * xN = 15cm * 3N, so we find 45 Ncm = 5cm * xN so x must be 9 N.
• Once both of these forces are in place and the system is stationary, what (if anything) will happen if the glue holding the die to the tabletop comes loose?
answer/question/discussion: If the glue that is holding the die to the tabletop comes loose, the whole system will probably move and will therefore no longer be stationary. The rod, rubber bands, die, and everything in the system will move toward the person doing the pulling on the system.
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It took me about 10 minutes to do this assignment.
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&#Very good work. Let me know if you have questions. &#