(1) A-to-ground pressure P A = FS = GS = MGS = ρ VGS = ρ A GH = 2×103kg/m3× 9.8n/kg× 2× 0.05m =1960pa;

(2) According to "B cuts a part in the vertical direction and piles it right above A, at this time, the pressures of A and B on the ground are equal",

P' A =P B，F' A S A =ρgh B，

G A +△G B S A =ρgh B，

Then ρ×8h3×g+ρ△h×9h2×g4h2=ρg3h,

The solution is △ h = 49 h

Answer: (1) The pressure on the ground is1960 P A; ;

(2) The cutoff thickness △h of cube B is 49 h. 。