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The operative mechanic, and British machinist (v. 1)
The operative mechanic and British machinist - v. 1 Author:John Nicholson Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: THE OPERATIVE MECHANIC AND MACHINIST. OF THE ACTION OF FORCES. All matter is continually under the operation of forces, which, if acting upon it equall... more »y, and in opposite directions, maintain it in a state of rest. But if a newly created force act upon a body in such a direction, and to such an extent, as to overcome the forces under whose action that body, in common with all other matter, exists, the result will be motion communicated to that body; and in an exact proportion as that newly created force exceeded the amount of forces that were previously acting upon it in the opposite direction. For example, if a man lift a pound weight three feet from the ground, the amount of motion created by that action is exactly equal to the amount his newly created force exceeded the force of gravity or weight which acted on the matter: for if his force had not exceeded the force of gravity, it is manifest that that motion could not have been created ; and if the force of gravity had not existed, it is again manifest that the amount of motion would be exactly in proportion to the amount of the whole of the force he had applied. Again, if his force only exactly equalled, and did not exceed the force of gravitation, motion could not have taken place, and the body would have remained at rest. This state of rest, maintained by the contrary action of two equal forces upon a body, is called equilibrium. But the term equilibrium is most commonly applied when one or more bodies are, by the mere force of gravitation, maintained in a state of quiescence, or rest: thus, if a bar of iron, AB, fig. I, is supported at its centre C, it will balance, or remain horizontal, as the quantity of matter in C A is exactly equal to that in C B, and the amount of the gravitating force proportional to the...« less