a) 0.3m/s
Mass of rifle, M = 5kg Mass of bullet, m = 50 gm = 0.05kg initial velocity of bullet, u = 30 m/s we have to find the U i.e; initial velocity of the rifle. fined velocity of bullet, v = 0 final velocity of rifle V = O Using, Conservation of linear momentum m x u + M x U = m x v + M x V 0.05 x 30 + 5 x U = 0.05 x 0 + 5 x 0 0.05 x 30 +5U = 0 5 U = -30 x 0.05 5 U = -15 U = -0.3 m/s