To test the strength of a retainment wall designed to protect a nuclear reactor, a rocket-propelled F-4 Phantom jet aircraft was crashed head-on into a
concrete barrier at high speed in Sandia, New Mexico, on April 19, 1988. The
F-4 phantom had a mass of 19,100 kg, while the retainment wall's mass was
469,000 kg. The wall sat on a cushion of air that allowed it to move during
impact. If the wall and F-4 moved together at 8.41 m/s during the collision,
what was the speed of the F-4 Phantom upon impact?