The mechanical engineer's pocket-book. A reference-book of rules, tables, data, and formulæ, for the use of engineers, mechanics, and students (1910)
Kent, William, 1851-1918 · New York, J. Wiley & sons · leaf 109
or is so small that it may be neglected. Describing an arc with a radiusof 12 inches subtending an angle of 30°, the error is 1/50000 of an inch. To measure an arc when it subtends a large ansrle, bisect it and measureeach half as before—in this case making 5 = length of the chord of half thearc,… … = 2VW (272 - m), = 2R sin l/2/,= 2Tcosy2I. = R exsec 1/2/, = R tan 1/2 ^ tan 1/4 7,= T tan 1/4/. ^x ^p.Su / 7 —* = R sin I, = = q2 + &22a a cot 1/21- _c2__d2__ c2 + An.2a 2m 8m m Fig. 70. /2JKmT= ^R{2R - ^(272 + c) (272 - c))f = 272 sin 1/4/.= 72 T _^1: 2R■■ R sin 1/2/ tan 1/4/, \/(# + !)(#-…
Mechanical engineering
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