1. The problem statement, all variables and given/known data A hot - air balloon experiences an acceleration of 1.10 m/s^2 [down]. The total mass of the balloon, the basket, and the contents of the basket is 315 kg. The balloonist wishes to change the acceleration to zero. There is no fuel left to heat the air in the balloon. Determine the mass of the ballast that must be discarded overboard. [NEGLECT AIR RESISTANCE] 2. Relevant equations Newtons second law equation : F = mA Free body diagrams are also important 3. The attempt at a solution I drew a free body diagram for the hot air balloon and I noticed there were two forces: The force of gravity and the upward (buoyant) force on the system. I calculated the upward force on the system to be approximately 2.7 * 10^3 N [up]. However I'm totally stuck on what to do next. Please help and many thanks in advance!