As shown in the figure, regardless of the mass of the plastic cup placed on the horizontal table, pour 200g water into the cup with a water depth of 20cm; then gently put 40g wood block into the cup, and the wood block floats after it is still, and the water surface rises by 4cm (water does not overflow, g = 10N / kg)? (2) What is the buoyancy of the block? (3) What is the pressure of the bottom of the cup on the horizontal table?

As shown in the figure, regardless of the mass of the plastic cup placed on the horizontal table, pour 200g water into the cup with a water depth of 20cm; then gently put 40g wood block into the cup, and the wood block floats after it is still, and the water surface rises by 4cm (water does not overflow, g = 10N / kg)? (2) What is the buoyancy of the block? (3) What is the pressure of the bottom of the cup on the horizontal table?

(1) The pressure of water on the bottom of the cup is p = ρ GH = 1000kg / m3 × 10N / kg × (0.2m + 0.04m) = 2400pa; (2) the buoyancy of the wood block f = g wood = mg = 0.04kg × 10N / kg = 0.4N; (3) the pressure of the bottom of the cup on the horizontal table f = g wood + m water g = 0.4N + 0.2kg × 10N / kg = 2.4n