The ducted fan unit of mass m is supported in the vertical position on its flange at A....

The ducted fan unit of mass m is supported in the vertical position on its flange at A. The unit draws in air with a density ρ and a velocity u through section A and discharges it through section B with a velocity v. Both inlet and outlet pressures are atmospheric. Write an expression for the force R applied to the flange of the fan unit by the supporting slab.