00:01
In this exercise, we have three force vectors, a, b, and c shown here in the figure, and are going to find which fourth force vector would be such that the sum of the four vectors would be zero.
00:18
So, first of all, notice that here we have the y and x axes.
00:24
Y axis is pointing upwards, the x -axis to the right.
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And let's define the vector d, such that the sum of vector d with a, b, and c is equal to 0.
00:41
So this means that d is equal to minus a plus b plus c.
00:50
Okay, so in order to find what d is, we need first to find a, b, and c in their component forms.
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So let's start with a.
00:59
Notice that a is equal to axi plus a y j.
01:08
Ax is the magnitude of a times a cosine of 30.
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And we can find that only using basic trigonometry.
01:20
You can consider a to form a right triangle.
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And the legs of the triangle are ay and ax...