# Tracts: Containing: I. Mechanics, Or the Doctrine of Motion: II.

F. Wingrave, 1793 - 302 sider

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Side 75 - As the distance between the body to be raised, or balanced, and the fulcrum, or prop, is to the distance between the prop and the point where the power is applied, so is the power to the weight...
Side 75 - It is a principle in mechanics, that the power is to the weight as the velocity of the weight is to the velocity of the power.
Side xx - In the early part of his life he attempted to teach a few scholars ; but whether from his concise method, for he was not happy in explaining his ideas, or the warmth of his natural temper, he made no...
Side 96 - In thofe of the third kind, at the power, and dirninifh proportionally from that point. The axles of wheels and pullies, the teeth of wheels, which bear greater weights, or act with greater force, muft be made ftronger. And thofe lighter, that have light work to do. Ropes muft be fo much ftronger or weaker, as they have more or lefs tenfion. And in general, all the parts of a machine muft have fuch a degree of fircngth as to be able to perform its office, and no more.
Side ix - One of these hats of immense superficies, had, by length of time, lost its elasticity, and its brim began to droop in such a manner as to prevent his being able to view the objects before him in a direct line. This was not to be endured by an optician ; he therefore took a pair of...
Side 134 - MISCELLANEOUS PROBLEMS. To find the specific gravity of a body heavier than water. RULE. — Weigh the body in water and out of water, and divide the weight out of water by the difference of the two weights. EXAMPLE. — A piece of metal weighs 10 Ibs. in atmosphere, and but 8i in water ; required its specific gravity.
Side 124 - For the preffure is as the weight, and the weight is as the height of a column of the fluid. PROP. PROP. LXV. Flg...
Side 76 - C (fig. 555.) of the pulley we draw the horizontal diameter AB; then will AB represent a lever of the first kind, its prop being the fixed centre C, from which the points A and B, where the power and weight act, being equally distant, the power P is consequently equal to the weight W. 1317. Hence, if the pulley be put in motion, the power P will descend as fast as the weight W ascends : so that the power is not increased by the use of the fixed pulley, even though the rope go over several of them....
Side 83 - ... so that it may revolve freely, carrying round with it the attached wheel. On the axis is coiled a rope which sustains the weight ; and round the periphery of the wheel is coiled another rope, in a contrary direction, to which is suspended the power. Then supposing the machine to be put in motion, the velocity of the power will be to that of the weight, as the circumference of the wheel to that of the axle ; for it will be perceived that the power must sink through a space equal to the circumference...
Side 199 - C, to D and F, for. the circle DF ; and from A, the projecting point, draw AF/, and AD^, then df will be the tranfverfe axis of the ellipfis. But if D fall beyond the line RE, as. at G,. then: draw. a fine from G backward thro' A to D, and then df is the tranfverfe of an hyperbola.