Lemmas of mechanics necessary for a more accurate analysis of the motive force exerted by the muscles
Two forces A and B (Fig. 3, Tab. IX) pull the extremities of a stick CD attached to the rods NO, OP. The forces pull in the directions MQ and MF, at right angles to each other, and are in equilibrium. Their moments are equal. I claim that the ratio of the forces A/B is equal to CM/MD, i.e. the ratio of the corresponding segments of the two main rods intercepted by the stick CD. Perpendiculars GC, GD are drawn from C and D to the main rods. They intersect at G. From G a perpendicular GH is drawn to CD at H. From H perpendiculars HK and HL are drawn to GC, DG. A force I is applied at H. Its moment is equal to the moment of A or of B. Force B is removed. Since the moments of A and I are equal and the intersection C is mobile along CF1, the ratio of the forces A/I is equal to the ratio of the height HK to the length CH or equal to CM/CD as a result of the similarity of the triangles.
KeywordsIntercostal Muscle Equal Force Small Machine Equal Moment Suspended Weight
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