Physics of the Human Body (Biological and Medical Physics, Biomedical Engineering)
Irving P. Herman
Format: PDF / Kindle (mobi) / ePub
Richard P. McCall's fascinating book explains how basic concepts of physics apply to the fundamental activities and responses of the human body, a veritable physics laboratory.
Blood pumping through our veins is a vital example of Poiseuille flow; the act of running requires friction to propel the runner forward; and the quality of our eyesight demonstrates how properties of light enable us to correct near- and far-sightedness.
Each chapter discusses a fundamental physics concept and relates it to the anatomy and physiology of applicable parts of the body. Topics include motion, fluids and pressure, temperature and heat, speech and hearing, electrical behaviors, optics, biological effects of radiation, and drug concentrations. Clear and compelling, with a limited amount of math, McCall's descriptions allow readers of all levels to appreciate the physics of the human physique.
Physics of the Human Body will help curious high school students, undergraduates with medical aspirations, and practicing medical professionals understand more about the underlying physics principles of the human body.
ﬂexion and extension, (b) pivot joint (1D joint), as in the atlantoaxial joint in the spinal cord for rotation, (c) saddle joint (2D), which is both concave and convex where the bones articulate, as in the joint between the ﬁrst metacarpal and the trapezium in the hand, (d) condyloid or ellipsoidal joint (2D), as in the metacarpophalangeal (knuckle) joint between the metacarpal and proximal phalanx for ﬂexion and extension, abduction and adduction, and circumduction, (e) plane joint (2D), as in
normal force in measurements made on several men in the early 1930s at Columbia University . This vertical force increases and then decreases, and while it is applied the center of mass accelerates upward and travels a distance s. The work W done on the center of mass during this phase is s FV (t)dz. W = (3.50) 0 (Note that to perform this integration FV (t) needs to be converted to a function of z.) This gets converted into the vertical kinetic energy so s FV (t)dz = 0 1 2 mb vTO =
the beginning of the throw, the so-called initial conditions. From the diagram in Fig. 3.43a, we see that at the beginning, t = 0, the arm is straight, so θ(t = 0) = π(= 180◦ ). Because the ball is still, dθ(t = 0)/dt = 0. At the end of the throwing motion the ball is released, say at tﬁnal . This could occur at θ = 0, so θ(tﬁnal ) = 0. In a normal throwing motion the release occurs before θ = 0. In any case, if the release time is tﬁnal , the ball leaves the hand with a speed vB = |Ldθ(tﬁnal
thinnest bones absorbing the impact. The tibia near the ankle has a radius r ∼ 1 cm 158 3 Motion and a cross-sectional area A ∼ 3 cm2 = 3 × 10−4 m2 . During impact the force per unit area in this region of the tibia is 7 × 104 N F 2 2 = = 2.3 × 108 N/m = 230 N/mm . A 3 × 10−4 m2 (3.102) Upon compression bones typical break when subjected to a force per area above ∼1.7 × 108 N/m2 = 170 N/mm2 = 170 MPa. This damage threshold is called the ultimate compressive stress (UCS, Chap. 4). The
ball and bat, and using that result in (3.114) gives − vball v Wbat,ideal = ball . Wball vball + evball (3.115) Using the typical pitch speed of vball = −80 mph and the batted ball speed to hit a home run vball = 110 mph, the “optimized” bat weight is Wbat = mbat g = 15 oz, which is smaller than the actual weight of bats that are used by adults. (Is the assumption that the initial kinetic energy should be minimized really reasonable?) Another way to determine the ideal bat weight combines a