876 OUTLINES Of NATURAL PHILOSOPHY. 



Resistance of the Air to Projectiles. 



37%. Though we should be led, as in hydraulics, 

 to conclude that the resistance which air makes to 

 moving bodies* is as the square of their velocities, 

 experiment appears to prove, especially when the 

 velocity is great, that the resistance is partly pro- 

 portional to the square, and partly to the simple 

 power of the velocity. 



The resistance to the same ball, its velocity being v y 

 is m v*+nv ; where m and n are given co-efficients, 

 BUTTON'S Course of Mathematics, vol. in. p. 278. 



In this formula m = .00002576 = -- , and 



n = .00388 = -, the diameter of the ball 



being 1.965 inches. 



Hence for any ball of which the diameter is d, 

 m = . 00000666, and w=r .001, that is, 



m= Sooooo > andw = -Io6o ; 



and 



