A biomechanical model of the lumbar region of the human trunk is shown. The forces acting...

A biomechanical model of the lumbar region of the human trunk is shown. The forces acting in the four muscle groups consist of FR = 35 N for the rectus. FO = 45 N for the oblique. FL = 23 N for the lumbar latissimus dorsi, and FF = 32 N for the erector spinae. These loadings are symmetric with respect to the y-z plane. Replace this system of parallel forces by an equivalent force and couple moment acting at the spine, point O. Express the results in Cartesian vector form.