(1)∵ The buoyancy of an object is equal to the gravity of the displaced liquid.

∴ Buoyancy F B =G Row B = 0.5N is on the ball in the B cup;

(2) the ball b floats,

∴ρb >ρball,

A ball sinks, sinks to the bottom,

∴ ρ A

∴ density of two liquids:

ρB >ρA；

Also, the liquid levels of the two containers are equal, p=ρgh,

∴ pressure of two liquids at the bottom of the container: P B > P A.

So the answer is: 0.5;