RECOIL

RECOIL, or REBOUND, the starting backward of a fire-arm after an explosion. Mersennus tells us, that a cannon 12 feet in length, weighing 6400 lb. gives a ball of 24 lb. an uniform velocity of 640 feet per second. Putting, therefore, $W=6400$, $w=24$, $V=640$, and $v$ the velocity with which the cannon recoils; we shall have (because the momentums of the cannon and ball are equal) $Wv\; =\; wV$; and so $v\; =\; \backslash frac\{wV\}\{W\}\; =\; \backslash frac\{24\; \backslash times\; 640\}\{6400\}\; =\; 2.4$; that is, it would recoil at the rate of 24 feet per second, if free to move.