quiz ?

The helicopter can produce a maximum downward air speed ( v = 24 m/s ) in a slipstream of a diameter ( D = 9 m). Knowning that the weight of the helicopter and the crew is ( 15 kN ) and assuming air density rho ( ρ = 1.21 kg/m^3 ), determine the maximum load that helicopter can lift while hovering in midair. ( 29.3 kN )

Thankyou.