Page:A Treatise of the Mechanical Powers - Motte - 1733.djvu/140

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Of the PLANCE

neither parallel to the Plane as F Q, nor perpendicular to it as D E.

The Force applied in the Direction H E, being fuppofed equal to the Force applied at F in the Direction F G, let the Line H E be made equal to F E, Draw H K perpendicular to D E, cut- ting D E in K. Then will the Force H E be resolved into two Forces, H K and K E. The Force K E being per- pendicular to the Plane, or which is the same thing to F G, will by what was just now shewn, have no Effect at all, The Force H K being parallel to the Plane, or to F G, supports the Weight; and by what has been shewn before, the Force H K is to the Force H E, as the Line H K is to the Line HE or F E, But H K is to H E, as fhe Sine Com- plement of the Angle K H E, or which is the same, of the Angle H E F, to Ra- diu, Now the Angle H E F is the An- gle in which the Line of Direction of the oblique Force H E is inclined to the Plane, or to F G, That Angle is called the