[Q] Buoyancy in Air: What is the minimum volume of a helium-filled balloon to remain in the sky at one position? Here's some more info: Total mass of the balloon before being inflated: 80 kg Density of helium: 0.179 kg/m3, Density of air: 1.28 kg/m3 The balloon contains helium at a pressure of 1.0 atm Think about: What is the total weight of the balloon? Why can a balloon float if it's at 1atm of pressure? Explain your reasoning and set up the equations.