A spacecraft is launched from the ground. The engineers who designed it didn't learn their mechanics very well because they spent too much time partying. As a result spacecraft quickly breaks up 1000 m off the ground into two pieces. The first has a mass of 10000 kg and the second a mass of 20000 kg. The first one is seen flying off initially in the horizontal direction with a velocity of 100 m/s due east. What was the velocity of the second piece? Ignore air resistance.