A pyrotechnician releases a 3 kg firecracker from rest. At t = 0.4 s the firecracker is moving downward with speed 4, when it begins to explode into two pieces with masses m top = 1 kg and mbottom 2 kg. At the end of the explosion (t = 0.8 s), the top piece is moving S = upward with speed 4 m - S A. What is the magnitude and direction of the total impulse exerted on the entire firecracker during the explosion? Initial t = 0.4 s m = 3 kg || = 4 m/s Final t = 0.8 s 16= 4 m/s top mtop = 1 kg mbottom = 2 kg bottom=? B. What is the speed of the bottom portion of the firecracker?