96
ARCHIMEDES
where k is the axis of the segment of the paraboloid cut off by
the surface of the fluid*)
V. Prop. 10 investigates the positions of stability in the cases
where h/\p> 15/4, the base is entirely above the surface, and
s has values lying between five pairs of ratios respectively.
Only in the case where s is not less than (h — f p) 2 /h 2 is the
position of stability that in which the axis is vertical.
BAB 1 is a section of the paraboloid through the axis AM.
G is a point on AM such that AC — 2 CM, K is a point on CA
such that AM-.CK — 15:4. CO is measured along CA such
that CO = \p, and B is a point on AM such that AIR = | CO.
A 2 is the point in which the perpendicular to AM from K
meets AB, and is the middle point of AB. BA 2 B 2 , BA^AI
are parabolic segments on A 2 M. 2 , A a M :i (parallel to AM) as axes
and similar to the original segment. (The parabola BA.,B tl
is proved to pass through G by using the above relation
AAI:GK =15:4 and applying Prop. 4 of the Quadrature of
the Parabola) The perpendicular to AM from 0 meets the
parabola BA 2 B 2 in two points P 2 , Q 2 , and straight lines
through these points parallel to AAI meet the other para
bolas inP l; Q 1 and P 3 , Q 3 respectively. P X T and Q, U are
tangents to the original parabola meeting the axis MA pro
duced in T, U. Then
(i) if s is not less than AR 2 : AM 2 or (h-%p) 2 :h 2 , there is
stable equilibrium when AM is vertical;
(ii) if s<
with its
only, but
and the
than U ;
(hi a) if i
point of 1
at an ang
(iiib) if s
point of i
to it at ai
(iv) if s >
equilibriu
(v) if s<
the base
inclined t
It renu
vestigatio
or throng
This is
required t
colours, 01
the problei
and the s
unknowns
bulls and '
the numb
following (
(I)
(II)
1523.2