p =ρGH = 1× 103kg/m3× 10N/kg×0. 1m = 1000 pa；

(2) When the marker lamp is stationary:

F float A=G row =1kg×10n/kg =10n;

Tension of a rope:

FA=F floating a-g =10n-6n = 4n;

(3) The downward pulling force of the rope pair B is FB=FA=4N,

The buoyancy of float b is f float =GB+FB= 1N+4N=5N,

The volume of float b is:

V=V row =F floating ρ water g = 5n/kloc-0 /×103kg/m3×10n/kg = 5x10-4m3.

A: (1) foam a? The bottom water pressure is1000 pa; ;

(2) Zhang Liwei 4n of the chord at the bottom of A;

(3) The volume of float B shall be 5× 10-4m3.