铝块的体积为：V= m ρ = 2.7kg 2.7×103kg/m3 =0.001m3；则铝块的底面积为S=0.01m2；铝块的重力为：G=mg=2.7kg×10N/kg=27N；即压力为F=27N，压强为：P= F s = 27N 0.01m2 =2700Pa．答：铝块对水平桌面的压强为2700Pa．
