A man is trying to lift 60.0 kg off the floor by bending at thewaist. Assume that the man’s upper body weighs 455 Nand the upper body’s centre of gravity is 38 cm from thesacrum (tailbone).
(a) If, when bent over, the hands are a horizontal distance of 76cm from the sacrum, what torque must be exerted by the erectorspinae muscles to lift 60.0 kg off the floor? (The axis of rotationpasses through the sacrum.)
(b) When bent over, the erector spinae muscles are a horizontaldistance of 44 cm from the sacrum and act at a 12 degree angle above the horizontal. What force dothe erector spinae muscles need to exert to lift the weight?
(c) What is the component of this force that compresses the spinalcolumn?