Learning Goal: I'm working on a biomedical engineering question and need an explanation and answer to help me learn.Consider a person performing an elbow flexion movement with the top always supported on a frictionless horizontal table. At a certain moment of movement (illustrated in the figure below), the elbow is flexed at 90 degrees with an acceleration of 1800 degrees/s2 ; angular velocity and acceleration of the shoulder are always zero. model the member upper arm with two bodies: upper arm and forearm + hand (forearm hand). The coordinates (x, y) that define these two segments are shown in the figure. The person's mass is 100 kg. a) Calculate the resultant joint force and moment of joint force at the shoulder.