An operator is holding a tool for a horizontal drilling task. the woman's elbow is flexed 45 degrees. The length of her forearm is 0.4m and the drill has mass of 5kg. Her forearm/hand weighs 20N and its center of mass is half the distance between the tool and the joint center.
a) what is the reaction force at the joint? be sure to draw and label the free body diagram of the system.
b)qualitatively describe how the muscle force would change if the elbow was flexed 90 degrees from vertical? include a drawing of the new system