A balloon filled with helium gas has an average density of rhob = 0.24 kg/m³. The density of the air is about rhoₐ = 1.23 kg/m³. The volume of the balloon is Vᵦ = 0.027 m³. The balloon is floating upward with acceleration

Express the weight of the balloon, W, in terms of rhoᵦ and Vᵦ.