Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . If thecentre of gravity is not in the central line or longitudinalaxis of the hammer-head, then there is a tendency to bringthe hammer down on the edge of the face, and not on theface. If this defective construction be great, the musclesof the wrist may not be strong enough to counteract thetendency. If the defective construction be slight, then thework is often marked with angular indents. Arrangementstoo may be required for modifying the intensity of the blowwhile retaining the effec
Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . If thecentre of gravity is not in the central line or longitudinalaxis of the hammer-head, then there is a tendency to bringthe hammer down on the edge of the face, and not on theface. If this defective construction be great, the musclesof the wrist may not be strong enough to counteract thetendency. If the defective construction be slight, then thework is often marked with angular indents. Arrangementstoo may be required for modifying the intensity of the blowwhile retaining the effects resulting from a heavy hammer,where a light one would be inefficient. In dealing with hammers the following questions claimcareful consideration: What power or energy is in a hammer of known weight moving at a knownvelocity, if brought to a state of rest by impact on a block ? Can this impact effect of. a hammerbe converted into simple pressure, and be stated as a load or weight placed where the impact isrequisite to produce the same effect as the impact did ? If the mode of solving the first question. 80 HAMMERS, HAND. be made clear, then the answer to the second can be readily obtained. The measurable elementswhich affect the result are a variation in the mass of the hammer-head and a variation in the lengthof the handle. By a varied mass there is a varied weight in the hammer; by a varied length ofhandle there will, with the same muscular effort, be a varied velocity in this mass; and upon a com-bination of mass and velocity depends the produced energy. (See Dynamics.) Now, if a mass ofmetal moving at a known velocity strike an object, the energy of the blow results from the condi-tions at the moment of impact. For example, the work done in the hammer H, Fig. 2235, as itstrikes the nail N, does not depend upon its velocity through the arc Q iV, but only upon its velocitywhen commencing contact with the nail. Hence, 60 long as the material which gives the blow andthe mass
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