. Graphical and mechanical computation . DARC Y EQUA T/OA/-FL OW OF STEAM //V P/PES. Fig. \\b. 82 NOMOGRAPHIC OR ALIGNMENT CHARTS Chap. IV Since we have two unknown quantities we can of course get various com-binations of these to satisfy the equation. By means of the chart to be constructed these combina-tions of width and height arereadily seen, and any desiredcombinations may then bechosen. We have an equation in-volving five variables of theform (V), case (3), and intro-ducing an auxiliary quantity,Q, we shall separate it intotwo equations; thus, F W , Q IP T = -pr and ?= = L Q B 9 We now
. Graphical and mechanical computation . DARC Y EQUA T/OA/-FL OW OF STEAM //V P/PES. Fig. \\b. 82 NOMOGRAPHIC OR ALIGNMENT CHARTS Chap. IV Since we have two unknown quantities we can of course get various com-binations of these to satisfy the equation. By means of the chart to be constructed these combina-tions of width and height arereadily seen, and any desiredcombinations may then bechosen. We have an equation in-volving five variables of theform (V), case (3), and intro-ducing an auxiliary quantity,Q, we shall separate it intotwo equations; thus, F W , Q IP T = -pr and ?= = L Q B 9 We now construct a Z chart. Fig. 42a. for each of these equations, the two charts having the ()-axis in the first of these equations our scales are x = TtiiF, y = m2 (L), z = mzW, q = mt (Q), and we have the following table: Scale FLW Limits up to 2000up to 40up to 15,000 Modulus mi = = = Equation Length x = F 6 y = ;L 12 z = W 12 nii m^niz g = Q The F- and W-scales are placed on the same axis (Fig. 42a) and startingfrom the same origin, and the L- and Q-scales on a parallel axis, but theQ-scale is not graduated. For the second equation our scales are q = mbQ, r = m6B,and we have the following table: 5 = m7H2, t = m$ (9), Scale Limits Modulus Equation Q m5 = q = Q B up to 10 m6 = 1 r= iB H up to 12 m7 = s = H2 m6m7rn = = T / = Q Length m5 Art. 42 DISTRIBUTED LOAD ON A WOODEN BEAM 83 15,000 14,000- 13,000 12,000
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