Opening celebration slogan under inflatable balloon

Solution: Solution: According to the stress analysis of the balloon, as shown in the figure:

F float = ρ GV =1.29kg/m3×10n/kg× 9m3 =116.1n;

g = Mg = 10kg× 10N/kg = 100n；

According to the force balance, F- tension =F buoyancy-g =116.1n-100n =16.1n;

So choose B.