A diagram of the human arm is shown holding a heavy iron ball (mass 5.0 kg).

The triceps muscle connects to the forearm 3.0 cm to the left of the elbow joint, while the biceps muscle connects 5.0 cm to the right. Each of the muscles can exert an upward force on the forearm when needed. The forearm and hand together itself have a mass of 4.0 kg and a center of mass 15 cm to the right of the elbow joint.

Q. Instead of holding a ball, the person turns their hand over and presses down on the end of a table, exerting a force of magnitude 50 N. The arm still makes a right angle as shown. In this situation, the force exerted by the biceps is approximately zero. What magnitude force must the triceps be exerting?