One position during shovelling snow or soil is shown in the figure. Assume this is an equilibrium poison. (a) If the shovel and contents have a mass of 10 kg, with a center of mass 1 m from the lumbar vertebra, find the torque about that vertebra. (b) If the back muscles are 5 cm behind the center of the disc, find the magnitude and direction of the muscle force needed for equilibrium. (c) Find the force on the intervertebral disc. (d) If the abdominal muscles of the person are strong and can provide some upward force, would that help relieve stress to the back muscles and the disc? Why?

Load Abdominal pressure Pivot vertebra - Vertebra bone Disk Tension from back Extensor muscle