Determine the density of a homogeneous body, the weight of which in air is P = 2.8 N, and in water P1

Determine the density of a homogeneous body, the weight of which in air is P = 2.8 N, and in water P1 = 1.69 N. The buoyancy force in the air should be neglected.

Data: Rvoz is the weight of the specified homogeneous body in air (Rvoz = 2.8 N); Rvod – weight in water (Rvod = 1.69 N).

Const: ρw is the density of water (according to the condition assumed ρw = 103 kg / m3).

To find out the density of the indicated homogeneous body, we use the equality: Rozd – Pvod = FA (Archimedes’ force) = ρw * g * Vt = ρw * g * mt / ρx = ρw * g * Rozd / (g * ρx) = ρw * Rozd / ρx, whence we express: ρx = ρw * Rozd / (Rozd – Rvod).

Let’s perform the calculation: ρx = ρw * Rozd / (Rozd – Rozd) = 103 * 2.8 / (2.8 – 1.69) ≈ 2522.5 kg / m3.

Answer: The density of the indicated homogeneous body is 2522.5 kg / m3.