Now many buildings use hollow bricks to build walls. As shown in the figure for a building material factory production of a specification of 200mm × 150mm × 100mm rectangular hollow brick, each brick quality of 4.5kg. The material density of this brick is 2.5 g / cm3. (1) What is the gravity of this brick? (G 10N / kg) (2) What is the volume of the hollow part of each brick? (3) What are the benefits of using this hollow brick and what to say
∵ ρ = mV, ∴ the volume of the solid part of the hollow brick: V real = mρ = 4
5kg25 the weight of the brick: G = mg = 4
5kg × 10N / kg = 45N; × 103kg / m3 = 18 × 10-3m the volume of the hollow brick: V = 200mm × 150mm × 100mm = 02m × 015m × 01m = 3 × 10-3m V = VV = 3 × 10-3m3- 18 × 10-3m3 = 12 × 10-3m3; the benefits of using hollow brick is: saving materials; insulation noise; reduce wall gravity A: the weight of this brick is 45N; the hollow part of each brick volume of 12 × 10-3m3; the benefits of using hollow brick is: saving materials; insulation noise;