A 12.0 g bullet leaves a rifle with a speed of 860.0 m/s. What should be the minimum mass of the rifle in order that its recoil speed (the backwards speed of the rifle after the bullet is fired) cannot possibly exceed 2.60 m/s? If the barrel has a length of 0.70 m, calculate b) the time the bullet is in the rifle c) the net force on the bullet and d) the net impulse on the bullet