A spaceship of mass 2.1×10^6 kg is cruising at a speed of 5.0×10^6 m/s when the antimatter reactor fails, blowing the ship into three pieces. One section, having a mass of 4.8×10^5 kg , is blown straight backward with a speed of 2.3×10^6 m/s . A second piece, with mass 8.4×10^5 kg , continues forward at 1.0×10^6 m/s .

What is the speed of the third piece? Assume that the initial speed of the ship is positive

1 answer

momentum is conserved, and since two pieces are in the direction of initial movement, the third cannot be in another track, it has to be in the same direction
Momentum:
2.1E6*5E6=4.8E5*(-2.3E6)+8.4E5*1E6+(2.1E6-4.8E5-8.4E5)V
solve for V