I am stuck on a part of my physics hw, please help if you can "Object A has mass mA = 7 kg and initial momentum vector pA,i = < 17, -8, 0 > kg · m/s, just before it strikes object B, which has mass mB = 11 kg. Just before the collision object B has initial momentum vector pB,i = < 3, 5, 0 > kg · m/s. The forces that A and B exert on each other are very large but last for a very short time. If we choose a time interval from just before to just after the collision, what is the approximate value of the impulse applied to the two-object system due to forces exerted on the system by objects outside the system?" i already calculated the total momentum of the system to be <20, -3, 0> kg m/s but i just cant figure out how to calculate the impulse without a given force or time.