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Select point C in the Graphics window and click Apply next to Geometry under Details of "Force". Next to Define By, change vector to Components. Enter -4000 for Y Component.
Do the same for point D.
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Select point C in the Graphics window and click Apply next to Geometry under Details of "Force". Next to Define By, change vector to Components. Enter -4000 for Y Component.
Do the same for point D.
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