The volume of a wood block is 200cm3, and its density is 0.8 × 103kg / m3. After immersing it in water, let go. Why can't the wood block be suspended in water? What is the volume of the wood in the water when it finally floats on the water and is still?

The volume of a wood block is 200cm3, and its density is 0.8 × 103kg / m3. After immersing it in water, let go. Why can't the wood block be suspended in water? What is the volume of the wood in the water when it finally floats on the water and is still?

(1) The weight of wood block: M = ρ wood, V wood = 0.8 × 103kg / m3 × 200 × 10-6m3 = 0.16kg; the gravity of wood block: g = mg = 0.16kg × 10N / kg = 1.6n; when the object is completely submerged, V row = V wood; when it is submerged in water, the buoyancy: F floating = ρ water, gvwood = 1.0 × 103kg / m3 × 10N / kg × 200 × 10-6m3 = 2n ∵ f floating ∵ g, ∵ the object floats up, and finally floats, so it can't be suspended; (2) when the object is still, it can't be suspended, Floating on the water surface, then f floating = g = 1.6n; from F floating = ρ liquid GV discharge: V discharge = f floating ρ water, g = 1.6n1.0 × 103kg / m3 × 10N / kg = 1.6 × 10-4m3. Answer: (1) the buoyancy of wood immersed in water is greater than gravity, so it cannot be suspended under the water surface; (2) the volume of wood immersed in water when floating is 1.6 × 10-4m3