A ten newton block is hanging from a line, goes up and over a pulley and to the right at a 90 degree angle. It hits an equilibrium point. At this eq point a line leaves upwards of tension T2 at 45degrees. Also at this eq point a string hangs down of unknown N.(adsbygoogle = window.adsbygoogle || []).push({});

Here are the components to find the second block:

Fx = T2Cos45 + 10N

Fy = T2Sin45 - N

This yields a T2 of 14.1 which is plugged into Fy yielding an N of 9.96.

Why is the 10N in Fx added and not subtracted? The component for it (T1x) is 180 degrees from its origin of the x axis in quadrant 1. Cosines in quadrant 2 and 3 in trigonometry are both negative. Why are we adding the weight? It should be subtracted. Thanks.

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# + or - in an equilibrium problem

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