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- Thread starter nhmllr
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- #1

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- #2

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- #3

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Right- but why? Can you derive it from F = ma or something?

- #4

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I do not know if it can be derived from F=ma though, as a and f are always in the same direction... And if you apply a force on an object not through its center off mass then the object will rotate, not in the direction of the force. I believe F=ma assumes the force is through the center of mass and hence torque cannot be derived from it. I stand to be corrected though

- #5

russ_watters

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- #6

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You know what? That makes so much sense. Thank you.

m

- #7

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Yes, f=ma on lots of rigidly bound point particles leads to rotational acceleration which needs describing in an angular equivalent: torque = inertia tensor * angular acceleration. It is just the same equation but with rotation instead of translation.

- #8

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... why does the torque go up proportional to the distance from the fulcrum.... I can't think of a goodreason.

If you want to understand the lever [torque], think of it as an invention, a tool that... conservation ofenergy.As a lever pivots, one end moves further than the other, so in order for conservation of energy to be satisfied, the force has to be lower on that side.

J = [N * m] =

energy is concentrated on the other arm [r

if you put a weight [50 N] at 10 cm from the fulcrum the lever is balanced because energy is the same

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- #9

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This equation means more radius would lead to more angular momentum change and thus more effectively change the angular acceleration α. They follow the definition.

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