Question

I want to dunk. I want to dunk a 10 ft rim. I stand 5'8 inches with a standing reach of 7'1 inches. For me to dunk safely, i must jump approx 42 inch off the ground. If i run at 4.53 meters per second and jump at a 60 degree angle with 5354 N of force I should jump high enough to dunk a basketball. I want to focus on developing the force to dunk. On a free weight squat rack, at a practical speed, how much weight must i use to squat an equivalent of 5354 N worth of force (in lbs)?