. Elementary lessons in the physics of agriculture. Agricultural physics. [from old catalog]. 18 a lever of the third class, and a power of nine hundred be- comes necessary to move a load of thirty. The relation of power to weight in the case of any lever is expressed by the equation below, where P. equals power, W. equals weight, P. A. equals power-arm and W. A. weight-arm: P. xP. A. = W. X W. A. When any three terms in this equation are known the fourth may readily be found. How great a load may be moved by a power of thirty pounds acting on a lever having a power-arm of twenty and a weight-
. Elementary lessons in the physics of agriculture. Agricultural physics. [from old catalog]. 18 a lever of the third class, and a power of nine hundred be- comes necessary to move a load of thirty. The relation of power to weight in the case of any lever is expressed by the equation below, where P. equals power, W. equals weight, P. A. equals power-arm and W. A. weight-arm: P. xP. A. = W. X W. A. When any three terms in this equation are known the fourth may readily be found. How great a load may be moved by a power of thirty pounds acting on a lever having a power-arm of twenty and a weight-arm of three? P. xP. W. X W. A. 30 X 20 = W. X 3. 600 = 3 W. W. = 200 1bs. 30. The Two-horse Eveiier.—This is a lever of the second class where the whippletree clevis-pin acts as the fulcrum for each horse, the weight or load being carried by the center pin. As ordinarily constructed this instru- ment is designed to divide the work of moving the load equally between the two horses. This, however, is not done at all times unless the three holes lie in the same straight When the holes are bored as shown in Fiof. 7 the load is divided equally only when one horse is not behind the 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 King, F[ranklin] H[iram], 1848- [from old catalog]. [Madison, Wis. ] State journal printing company
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