Answer Happy

12. When you lean over, a series of large muscles, the erector spinae, pull on your spine to hold you up. The figure shows a simplified model of the spine as a rod of length L that pivots at its lower end. In this model, the center of gravity of the 320N upper torso is at the center of the spine while the 160N weight of the head and arms acts at the top of the spine. The erector spinae muscles are modeled as a single muscle that acts at an angle of 12° to the spine. Suppose the person in the figure bends over at an angle of 30° from the horizontal. What is the tension in the erector spinae muscle? (2000N)
12. When you lean over, a series of large muscles, the erector spinac, pull on your spine to hold you up. The figure shows a simplified model of the spine as a rod of length L that pivots at its lower end. In this model, the center of gravity of the 320N upper torso is at the center of the spine while the 160N weight of the head and arms acts at the top of the spine. The erector spinae muscles are modeled as a single muscle that acts at an angle of 12° to the spine. Suppose the person in the figure bends over at an angle of 30° from the horizontal. What is the tension in the erector spinae muscle? (2000N) 30° Effective location of erector spinae muscles Center of gravity of head and arms 12° Center of gravity of upper torso Pivot