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phy 231
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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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 pushpin 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 pushpin 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: ->->->->->->->->->->->-> :
With one having 15 cm from the axis and the other only having 5cm, we know that one rubber band will exert 3 times the force of the other. That being said we use the .15m * 3 N = .45 m N to get the applied torque. The second torque will be equal an opposite, that being said we must have -.45 m N. Use the -.45 m N / .05 m to find the force applied at -9 N. The system itself must exert 9 N since it’s at equilibrium.
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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: ->->->->->->->->->->->-> :
The net force will be 3N + 9 N = 12 N and the system would move in the direction of the net force.
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&#Very good responses. Let me know if you have questions. &#