The Laws of Motion of a Cylinder, &c. 279 
Sdthitalipropreltin’ pf) Xivr + vite + 
WP eb kes ier Lae gery oe 
y 
fiber When equal quantities of matter in 
Vii-piate 
motion, are retarded by conftant but unequal Forces, 
the times required to reduce them to a ftate of reft 
are as their initial velocities directly, and as their 
retarding forces inverfely. Now in the prefent 
cafe we have the force of gravity = the weight 
of the fyftem = a-+dqce, and the velocity de- 
firoyed thereby in 1 fecond 25; on the other 
hand, the refiftance oppofed by the obftacle to the 
given column, has been found = 4, and the initial 
velocity of the fyftem after impact —= = = drawn 
into the fquare roots of the fpaces deferibed by the 
block in its unimpeded defcent; which fpaces are 
fuccellively =x 1, xX 1-+¢4,4%X%1 Ae con- 
BaF GT SH 255, 
a-+qdce od 
a 
wae Soe rid Veda. the time fpent 
hxatqdce 4ys 
in penetrating the Obftacle after the firft ftroke: in 
the fame manner it will be found, that the time re- 
guired for the fame purpofe after each fucceeding 
{troke 
tinued tox x r+ét  . Hence as 
fecond :: 
