The buoy, weighing 30 kg, floats on the water. The volume of the above-water part is 12 dm3.

The buoy, weighing 30 kg, floats on the water. The volume of the above-water part is 12 dm3. Determine the volume of the entire buoy.

Given: m (buoy mass) = 30 kg; V over. (volume of the surface of the buoy) = 12 dm3.

Reference values: ρ (density of the water in which the buoy is kept) = 1000 kg / m3.

1) Since the buoy is kept on the water, the force of gravity acting on it is compensated by the buoyancy force of Archimedes: Fт = Fa = m * g = ρ * g * Vp., Whence Vp. = m / ρ = 30/1000 = 30 * 10-3 m3 (30 dm3).

2) Volume of the whole buoy: V = Vab. + Vp. = 12 + 30 = 42 dm3.

Answer: The volume of the whole buoy is 42 dm3.