F float =V row *g*ρ water =1*10-3m3 * 9.8n/kg *103kg/m3 = 9.8n.

The fluctuation of f is less than g.

So sink to the bottom.

M object =G object/g = 2kg.

ρ= m/v = 2kg/ 1 * 10-3 m3 = 2 * 103kg/m3。