A spaceship of mass 1.90×10^6 kg is cruising at a speed of 4.50×10^6 m/s when the antimatter reactor fails, blowing the ship into three pieces. One section, having a mass of 5.20×10^5 kg , is blown straight backward with a speed of 2.20×10^6 m/s . A second piece, with mass 7.90×10^5 kg , continues forward at 1.20×10^6 m/s
What is the speed of the third piece?