A small plane climbs with a constant velocity of 250 m/s at an angle of 28° with respect to the horizontal. Which statement is true concerning the magnitude of the net force on the plane?
(a) It is equal to zero.
(b) It is equal to the weight of the plane.
(c) It is equal to the magnitude of the force of air resistance.
(d) It is less than the weight of the plane but greater than zero.
(e) It is equal to the component of the weight of the plane in the direction of motion.