104

Mechanics.

the Nature of Attraction or Gravity, thatif a Stone fall towards the Earth, the

Quantity

6. Now since IC=AG, we have this Analogy, Thedirect Stroke is to the oblique Stroke , as A C to A G, thatis , as Radius to the Sine of the Angle of Inclination ACG-Whence, it is evident, the less this Angle is, the moreoblique the Stroke, and the less its Force, because theless must AG (=;IC) be in respect of AC.

7. If the Bodies A, B, are Non-elaftic , in the LineGF, take CF=CG=AI, and this will be the horizon-tal Velocity of A after the Stroke, which will be thefame as before, and since the whole Force I C of theStriking Body A is known, we can find (by Annot.XXIII. 7.) what Part thereof remains after the Stroke,which let be exprefs’d byFD, (taken fromF totheRight)then drawing CD it shall represent the Motion and Di-rection of A after the Stroke, while B will go on towardsE with the Motion BE generated by the Stroke, (whichalso may be found as before) and will be equal to F D,if the Bodies A and B are equal.

8. If the Bodies are Elajlic , and B less than A, theDirection of A after the Stroke, {vise. CD) will makean Acute Angle with BE the Direction of B, or lie 011the Right of CF. If B be greater than A, it will bereflected so that CD will make an obtuse Angle withC£, or lie on the left of it. But if both the Bodies areequal, the whole Motion of A in the Direction CE willbe destroyed (by Annot. XXIII. 19.) and it will proceedwith only the horizontal Velocity in the Direction CF,making a right Angle wsth CE, the Direction of B.

9. It two Bodies A, J, in Motion, impinge on eachother in the Point C in the oblique Directions AC, BC,these are each resolvable into two, viz. AE and EC,

PlatelV. and BD and DC. Now since EC and DC are paral-■f‘3’ I 3 - lei, they cannot obstruct each other, so will be the sameafter the Stroke as before it. But AE and BD, beingopposite, will express the Forces with which the Bodiesstrike each other directly, and may be found by theRules above delivered.