# Answer to Question #29178 in Quantum Mechanics for betelhem

Question #29178

a woman weighs 475 N and a downward force of 17 N must be applied to keep her completely submerged in water what is the density of her body

Expert's answer

The buoyance force acting by water upon the woman is

F = rho_o * g * V,

where rho_o is the density of water, and V the volume of thewoman.

By the 3rd Newton's law, the same force is applied downwardsto compensate for the buoyance force, so it's 17 N by magnitude.

The woman's weight is P = m * g = rho_n * g * V, where rho_nis the density of the woman.

From these equations,

rho_n = P / (g*V) = rho_o * P/F = 1000 (kg/m^3) * 475 N / 17N = 27 941 kg/m^3.

F = rho_o * g * V,

where rho_o is the density of water, and V the volume of thewoman.

By the 3rd Newton's law, the same force is applied downwardsto compensate for the buoyance force, so it's 17 N by magnitude.

The woman's weight is P = m * g = rho_n * g * V, where rho_nis the density of the woman.

From these equations,

rho_n = P / (g*V) = rho_o * P/F = 1000 (kg/m^3) * 475 N / 17N = 27 941 kg/m^3.

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