Calculate the weight in water of a glass cube with a volume of 1 m3 if the density of the glass is 2600 kg / m3.

The weight of a glass cube in water will be equal to the difference between two directly opposite forces: gravity and buoyancy of Archimedes.
P = Ft – Fa = m * g – ρw * g * V, where m is the mass of the cube (m = ρst. * V, ρst. Is the density of the glass, (ρst. = 2600 kg / m ^ 3), V is the volume glass cube (V = 1 m ^ 3)), g is the acceleration of gravity (g = 9.8 m / s ^ 2), ρ is the density of water (ρ = 1000 kg / m ^ 3).
P = ρst. * V * g – ρw * g * V = 2600 * 1 * 9.8 – 1000 * 9.8 * 1 = 25480 – 9800 = 15680 N = 15.68 kPa.
Answer. The weight of the glass cube in water is 15.68 kN.