試題詳解

44. A balloon is to be filled with helium and used to suspend a mass of 300 kg in air. If the mass of the balloon is neglected, which of the following gives the approximate volume of helium required? (The density of air is 1.29 kg/m³ and the density of helium is 0.18 kg/m³ )
(A) 50m³
(B) 95m³
(C) 135m³
(D) 270m³
(E) 540m³