The groundwork of practical naval gunnery; a study of the principles and practice of exterior ballistics, as applied to naval gunnery, and of the computation and use of ballistic and range tables . 2in (14), and that for all other initial velocities results obtained by its use will be onlyapproximate. that the axis o£ the projectile coincides with the tangent to its Forcespath at every point, which is very nearly the case with modern rifled guns, theresultant action of the resistance of the air will likewise coincide with the axis, andthe trajectory will be the same as if the ma
The groundwork of practical naval gunnery; a study of the principles and practice of exterior ballistics, as applied to naval gunnery, and of the computation and use of ballistic and range tables . 2in (14), and that for all other initial velocities results obtained by its use will be onlyapproximate. that the axis o£ the projectile coincides with the tangent to its Forcespath at every point, which is very nearly the case with modern rifled guns, theresultant action of the resistance of the air will likewise coincide with the axis, andthe trajectory will be the same as if the mass of the projectile were concentrated at itscenter of gravity and moved under the action of two forces only, one the constant acting. 48 EXTEEIOE BALLISTICS vertical force of gravity, w, and the other the variable resistance of the air, — ^ -jtV^, C in the tangent. Figure 6 represents the trajectory, which is, of course, aplane curve, under the foregoing suppositions, and Figure 6(a) represents the twoforces acting upon the projectile at any point, the resistance of the air being denoted by — /, in which / is the retardation, -^, which we are now taking as proportionalto v^ dt. Figure 6 70. Taking vertical and horizontal axes at the point of departure, 0, let V bethe initial velocity, <^ the angle of departure, v the velocity at any point whosecoordinates are {x, y), and Vn the horizontal component of the velocity at that point. Ap is the radius of curvature of the curve at that point. Then, letting fc= ^ in equa-tion (18), we can put ,— = —hv-, and, since w has no horizontal component, the acceleration parallel to the axis of X is given by d-xdP ds = — 1cV~ COS but -TTT = -jT , V COS ^ = Vh, and v — , rdP dt dt dt ^:} =-]cvh whence (19) may be writtends dt (19) (20)(21) and integrating (21) between corresponding limits of Vh and s we get loge v^ Vcos<p Vh =? —Jcs Fcos <j) loge =JCS VH=Vcos€-^ (22) Next resolving along the normal, since the ac
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectballistics, bookyear1
