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Chapter 12, problem 3.
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For this problem, we're developing an equation to find where to place a mass in order to balance a simple lever.
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We start with a free body diagram of the lever.
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We have a beam marked here in red.
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We have two supports holding the beam up at o and p.
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But we're told for this problem to set the normal force at o equal to zero.
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So basically, that support is doing nothing.
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We can ignore that.
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We're going to be pivoting on point p.
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The lever is length l.
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Point o is l over 2 from the center of the map or center of the beam.
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D is how far the center is from the pivot point.
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And then x is what we're trying to find and that's where this second mass is going to be placed.
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Ultimately we have three points.
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They're providing a downward force and the pivot providing a single upward force.
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All we really need to look for here is the sum of the moments around p.
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So we'll start by identifying the forces.
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We've got m mass 1 times gravity.
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At this at point o, we got m, we'll call it mb for the beam times gravity, and that's at the center.
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And then we've got the m2 at g...