An iron ball weighing 1.47 n is hung under the spring scale. Immerse the iron ball in the water. The indication of the spring scale is 0.49 n. find out: (1) the buoyancy of the iron ball; (2) the volume of the iron ball; (3) is the iron ball hollow or solid?

An iron ball weighing 1.47 n is hung under the spring scale. Immerse the iron ball in the water. The indication of the spring scale is 0.49 n. find out: (1) the buoyancy of the iron ball; (2) the volume of the iron ball; (3) is the iron ball hollow or solid?

(1) The buoyancy of the iron ball is: f-f ′ = 1.47n-0.49n = 0.98n; (2) ∵ the iron ball is completely submerged, which can be obtained from f-f = ρ GV row, the volume of the iron ball is: v-ball = V row = f-floating, ρ water g = 0.98n1 × 103kg / m3 × 9.8n/kg = 10-4m3; (3) according to g = mg, the mass of the iron ball is: M = GG = 1.47n9.8n/kg = 0.15kg, which can be obtained from ρ = MV, the volume of iron in the iron ball is: V-iron = m ρ iron = 0.15kg7.9 × 103kg / m3 ≈ 1.9 × 10- Answer: (1) the buoyancy of the iron ball is 0.98n; (2) the volume of the iron ball is 10-4m3; (3) the iron ball is hollow