The mass of a granite stone with school motto is 31.8t and the density is 2.65 × 103kg / m3. It is erected on a horizontal base with a length of 4m, a width of 2M and a height of 0.5m (as shown in the figure). The contact area between the stone and the base is 2.12m2. The density of the known brick is 2.05 × 103kg / m3. The density of the cement mortar in the base brick joint is the same as that of the brick. (G is 10N / kg) Volume; (2) the pressure of stone to base; (3) the ratio of stone to base and base to ground

(1) The volume of granite stone: V stone = m stone, ρ stone = 31.8 × 103kg2.65 × 103kg / m3 = 12m3. Answer: the volume of granite stone is 12m3. (2) because the stone is placed on the horizontal base, the pressure of stone on the base is equal to the gravity of stone, that is: F stone = g stone = m stone, g = 31.8 × 103kg × 10

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