1. The problem statement, all variables and given/known data An 800 kg airplane travelling at a velocity of 120 m/s [30o N of E @ 20o above the horizon] collides with a stationary 1200 kg helicopter. If the velocity of the airplane after the collision is 65 m/s [40o N of E @ 60o above the horizon] what is the final velocity of the helicopter? 2. Relevant equations 3. The attempt at a solution I dont understand what to do with the 20 degrees above the horizon part in both the parts.