Hot air balloons work by heating the air and making it lighter. Do you think solar gathering material and/or a reflective mirror like material placed inside a balloon, could provide enough heat for lift?
k F/x (50*9.8/0.02) 24500 N/m. ω √k/m √ (24500 / 1050) 23.33 rad/s f ω /(2π) 3.71Hz.
They are smoke alarms and that means it's time to replace the back up batteries.
