A party balloon with a radius of 12.5 cm is filled with helium. How much weight can this balloon lift? Neglect the weight of an empty balloon. (density of air = 1.29 kg/m3, density of helium = 0.178 kg/m3)

Answer 1

volume of air displaced is v = 4/3 πr^3
weight = mg = volume*density * g
now subtract the weight of the balloon from that of the displaced air.