In the two cases below, the boxes stick together after the collision. Calculate the velocity of the final system in the two cases and take the direction to the right as positive. Case 1: What is the velocity of the final system? \fAn object at rest explodes into three fragments. The momentum vectors of the first two fragments are displayed below. ,1)\". (kg m/s) What is the speed of the third fragment, that has a mass of 135 g