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In this problem on the topic of equilibrium and elasticity, we are shown in the figure a construction bucket, which has a mass of 817 kg, and is suspended by a cable a attached at o to two other cables b and c.
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The cables make angles theta 1, which is 51 degrees and theta to 66 degrees with the horizontal.
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We are asked to find the tensions in cable a, b, and c, and we are given the axes as shown in the diagram.
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Now, since the bucket is in equilibrium, the tension force of cable a is equal to the weight of the bucket.
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So we get simply that ta is equal to w, and the weight of the bucket is its mass m times the acceleration due to gravity g.
00:48
Now, to solve for tb and tc, we use the quadrant axes defined in the diagram.
00:53
Cable a makes an angle of theta 2, which is 66 degrees with the negative y axis, and cable b makes an angle of 27 degrees with the positive y axis.
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Cable c is along the x -axis.
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Now the y components of the forces must sum to zero since the knot is in equilibrium.
01:13
This means that t b times the cosine of 27 degrees minus t -a times the x -a times the cosine.
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Cosine of 66 degrees must equal to 0...