physics
posted by jessica .
A jet (m = 4.00 105 kg), flying at 139 m/s, banks to make a horizontal circular turn. The radius of the turn is 3810 m. Calculate the necessary lifting force.

Regardless of the radius and velocity, the vertical component of the lift force must balance the weight, M g.
L cos A = M g
where L is the lift force. It is perpendicular to the wing, not straight up.
To get the vertical component, you must know the "banking angle", A. You can get this from
L sin A = M V^2/R (Tilting of the plane creates a horizontal lift component to provide the centripetal force)
To get L alone, square both equations and add
L = M*sqrt[g^2 + V^4/R^2]