Of Simple Motion, 17

*bat is, as 8 x 7 : to 6 x 5. But M,P & C, may be determined by com-mon Weight and Measure, for, bythe best Experiments yet known, thePerpendicular Descent of a heavy Bo-dy in Vacuum is id. 14 Feet in a Se-cond of Time, in which Fall it willacquire a Celerity double that Space,or 31.28, in a Second, as shall beafterward shewn, and, by Page 54^of Dr* Gravsand’ s Experiments, if.the falling Body is a Pound-Weight, it’s Momentum at the Endof the Fall will be 42 Pounds riear- 1

ly, and, by Law 4th, — --- ni ,

u

whence if c be equal to one Foot in

a Second 1 of Time, -- r = M -

32.28 J

tn the Momentum or Force of a Bo-dy of one Pound-Weight, movingat the Rate of one Foot in a Second*Hence,

D And,

1