15. A disk-shaped body with a 4 cm radius has a 320 N force acting through the center at an unknown angle 0, and two 40 N loads acting as a couple, as shown. All of these forces are removed and replaced by a single 320 N force at point B, parallel to the original 320 N force. What is the angle 0? 40 N A 320 N FB 4 cm B 40 N