A military airplane sometimes needs to refuel in mid-air, and another plane flies above it to add the fuel. If a plane with a mass of 7,800 kg is traveling with a velocity of 30 m/s and refuels by adding an additional 800 kg of jet fuel, what will its new velocity be? (Hint: This is a multi-step problem). I Have seen the answer is 27.2m/s, I was wondering how do you go from (8600) V2 to actually get 27.2m/s