Rebound, the starting backwards of a firearm after an explosion. Mersenne tells us, that a cannon twelve feet in length, weighing 6400 lbs, gives a ball of 24 lbs, an uniform velocity of 640 feet per second. Putting, therefore, \( W = 6400 \), \( w = 14 \), \( V = 640 \), and \( v \) = the velocity with which the cannon recoils; because the momentums of the cannon and ball are equal, we shall have \( Wv = wV \); and so \( v = \frac{wV}{W} = \frac{24 \times 64}{6400} = 2\frac{1}{4} \); that is, it would recoil at the rate of 2\(\frac{1}{4}\) feet per second, if free to move.