A probe in deep space is infested with alien bugs and must be blown apart so that the icky creatures perish in the interstellar vacuum. The craft is at rest when its self-destruction device is detonated, and the craft explodes into two pieces. The first piece, with a mass of 6.00×108 kg, flies away in a positive direction with a speed of 210 m/s. The second piece has a mass of 1.00×108 kg and flies off in the opposite direction. What is the velocity of the second piece after the explosion?