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Technology / Re: How does shifting the COG affect torque needed to rotate about a fixed fulcrum?
« on: 24/12/2015 17:06:56 »
Thank you so much! Your explanation-by-example is brilliantly clear, and makes perfect sense. But again, it's been a while... so let's just make sure that I do understand....
Let's say that the total length of the rod is 100cm, and that in the initial setup, each of the two 2Kg weights are arbitrarily placed 25cm from the fulcrum. In "part two", the 1Kg weight would then be 50cm from the fulcrum.
In the initial setup, the total moment of inertia required to rotate the system would then be 2(2Kg x 252cm) = 2500
In part two, the total moment of inertia required to rotate the system is (2Kg x 252cm) + (1Kg x 502cm) = 3750
So... in part two of my example, even though the rod remains statically "balanced" at its fulcrum point, the result of having moved the center of gravity away from that fulcrum point is a very significant increase in the total amount of torque required to rotate the system.
Remarkable.
And thank you, again. I have a strong feeling that this forum is about to very significantly impact my life!
Let's say that the total length of the rod is 100cm, and that in the initial setup, each of the two 2Kg weights are arbitrarily placed 25cm from the fulcrum. In "part two", the 1Kg weight would then be 50cm from the fulcrum.
In the initial setup, the total moment of inertia required to rotate the system would then be 2(2Kg x 252cm) = 2500
In part two, the total moment of inertia required to rotate the system is (2Kg x 252cm) + (1Kg x 502cm) = 3750
So... in part two of my example, even though the rod remains statically "balanced" at its fulcrum point, the result of having moved the center of gravity away from that fulcrum point is a very significant increase in the total amount of torque required to rotate the system.
Remarkable.
And thank you, again. I have a strong feeling that this forum is about to very significantly impact my life!