A 120-lb pilot files a jet trainer in a half vertical loop of 3600- ft radius so that the...

A 120-lb pilot files a jet trainer in a half vertical loop of 3600- ft radius so that the speed of the trainer decreases at a constant rate .Knowing that the pilot’s apparent weights at points A and C are 380 lb and 80 lb respectively, determine the force exerted on her by the seat of the trainer when the trainer is at point B.