Chapter 11, Problem 76GP

BIO The Masseter Muscle The masseter muscle, the principal muscle for chewing, is one of the strongest muscles for its size in the human body. It originates on the lower edge of the zygomatic arch (cheekbone) and inserts in the angle of the mandible. Referring to the lower diagram in Figure 11-57, where d = 7.60 cm, h = 3.15 cm and D = 10.85 cm, (a) find the torque produced about the axis of rotation by the masseter muscle. The force exerted by the masseter muscle is F_M = 455 N. (b) Find the biting force, P_B. exerted on the mandible by the upper teeth. Find (c) the horizontal and (d) the vertical component of the force F_B exerted on the mandible at the joint where it attaches to the skull. Assume that the mandible is in static equilibrium, and that upward is the positive vertical direction.