) 
( *9 ) 
^ 4 b a3 4- 4 b 3 a . . 0 
D = — — --- 1 • Atqrn eft A = 4 a b; unde eft 
D a a 4 - b b i _ „ . 
— = — = — D B quad. 
A 3 12 
Ex. 4. Situltimum exemplum inSphsera, cujus circulus 
maximus B t r, diameter A B, Sc 
centrum G. Tumduftislineisutin 
Schemate fatis patent, erit d = G sq: 
x p + Gm q : „ p. At fumma om- 
nium G s q : x p in re&a t r eft 
G s q : du&um in aream circuli dia- 
raetro t r defcripti. Item fumma 
omnium G M q .* x p in re &4 k i eft 
G m q: x aream circuli diametro k i 
defcripti.Unde ftatim conftat effeD = quater fiuentiipfius 
Gsq: in aream circuli cujus diameter eft t r. Sit ergo 
carea circuli cujus radij quadratum eft i, Sc fit G A = a, 
8c G s = x. Turn erit d = 4xxx x caa — cxx 
= 4c a 2 i x 2 — 4c x x 4 . Unde fumendo fluentem, 8c 
8 4 - 
faciendo x = a, erit D = — c a 5 - Eft autem A= — c a*. 
ij i 
Unde ? = 1 a a. 
A 5 
Ob a/Bnitatem folutionis libet his fubjungere Prob- 
lema de inventione Centri Percuffionis. 
Prop. 6 » Prob. 5. 
Corporis cujufvis circa datum pun ft urn rotati , invenire Cen- 
trum Percuffionis ; punftum fcilicet tale, ut Corpus in 
illud impingens, & ecidem opera folutum a punfto fuf • 
pen fonts, neque hue neque illuc inclined 
Primum conftat hoc punftum qusri debere in piano 
motus centri gravitatis. Si enim corpus refolvatur in 
D 2 lemeau 
