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Chapter 12, problem 2.
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For this problem, we're looking for general forms of equations that describe a simple object in equilibrium.
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We start, as always, with a free body diagram.
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The red line indicates the generic object in question.
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It starts at origin o in the lower left, extends length l up into the right, and terminates with a generic force f.
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It is tilted at an angle of theta.
00:29
The problem does not specify this, but i'm assuming that it's of uniform composition.
00:35
So the force of gravity at the center of mass is going to be in the center of the object at l over 2.
00:43
And with that, we can go ahead and get started, summing up our forces.
00:50
So we'll start with the forces in the x direction.
00:54
And we'll find that this one is fairly simple.
00:57
We only have the two forces in the x direction.
01:00
We have the reaction force plus the generic force on the end.
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And those equals 0.
01:11
So if we subtract f of x from both sides, we can solve for r of x as equal and opposite of f of x.
01:22
It means third law in action...