OF ENGINEERING FORMULÆ.
Mensuration of Solids.
Cylinder = Area of one end x length.
Sphere — Diameter 3 x 0 • 5236.
Segment of sphere — 0’5236 H (H2 + 3 IIs),
where H = height of segment and II = radius of
the base of the segment.
Cone or pyramid = Area of base X | perpen-
dicular height. ______
Frustum = |H (A + a+ VA x a.) When A
and a = Areas of the ends, H — Perpendicular
height.
Frustum of cone = 0 • 2618II (D2 + d- + D. d\
When D and d = the diameters of each end,
H = Perpendicular height.
Wedge = Area of base x J perpendicular height
Frustum of wedge =jH (A + a), when A and
a = Area at each end, H = Perpendicular height.
Length of Helices and Spirals.
x — Length of any helix or screw coil.
I — Length of any plain spiral.
L = Length of any conical spiral. __
C — Circumference of a circle equal in diameter
to the diameter of the helix or largest
diameter of the spiral.
c = Circumference of a circle equal the smallest
diameter of the spiral.
h = Number of revolutions of helix or spiral.
p = Pitch of revolutions.
h — Height of the conical spiral.
x = n VC^+J2.
657
_____________________________________________________
________
Ij ~ kJ I' 4*
2 u