. The elements of physiological physics: an outline of the elementary facts, principles, and methods of physics; and their applications in physiology. Biophysics. Chap. XLI.] LEVERS. 495 its distance from F to be 2 feet, its moment = 20. Now let the distance between F and p = 5 feet, a force of 4 pounds will give a moment of 20. Thus with these distances a force of 4 pounds at P will balance a force of 10 pounds at w. If p be made 5 pounds its moment will exceed that of w, and will pull the bar down towards it; w will be raised. The smaller weight acting through the longer distance will raise
. The elements of physiological physics: an outline of the elementary facts, principles, and methods of physics; and their applications in physiology. Biophysics. Chap. XLI.] LEVERS. 495 its distance from F to be 2 feet, its moment = 20. Now let the distance between F and p = 5 feet, a force of 4 pounds will give a moment of 20. Thus with these distances a force of 4 pounds at P will balance a force of 10 pounds at w. If p be made 5 pounds its moment will exceed that of w, and will pull the bar down towards it; w will be raised. The smaller weight acting through the longer distance will raise the heavier weight. FiS- of the First Order. The power and weight are in the inverse ratio to their arms. There are three classes of levers, according to the relative posi- tions of P, w, and F, the power, weight, and fulcrum. That which has been already described is a lever of the first order, where the fulcrum is between the power and the weight. Its advantage is that a small power may be made to raise a very heavy weight if the arms of the lever are properly adjusted. But it is apparent that the 112. 205. —Lever of Second Older. power must travel through a very considerable distance to raise a heavy weight even, a small amount. This is well shown in O Fig. 204, where the weight w is raised only a short distance, while the power performs a considerable excursion from P to P'. One great advantage evident from Fig. 203 is that by this lever two forces may readily be balanced by adjusting the position of F. Fig. 205 represents a lever of the second order, where the weight is between the power and the fulcrum. In it the power always acts through a longer arm. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original M'Gregor-Robertson, J. (Joseph), 1858-1925. Philadelphia, H. C. Lea's son & co.
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