Physics of the Human Body (Biological and Medical Physics, Biomedical Engineering)

Physics of the Human Body (Biological and Medical Physics, Biomedical Engineering)

Irving P. Herman

Language: English

Pages: 783


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.











N (320 lb) and R 2,100 N (470 lb). The origin of hip problems is clear: The force from the hip is much greater than the body weight because of the large moment arms. We next examine a variation of this problem. The person now uses a cane to provide support on the left side while standing on his or her right leg (Fig. 2.18). As shown in Fig. 2.19, the cane is 30.5 cm (1 ft) from the body midline. It is supported by and pushed down by the left arm or shoulder. Consequently, there is a normal force

diagram of the kneecap (patella) in equilibrium. (From [86]) 64 2 Statics of the Body Fig. 2.27. Force diagram of the foot on tiptoe, showing that they form a concurrent system. (From [86]) and 2.28 show the forces when someone stands on tiptoes on one foot. The reaction force on the talus bone of the foot is in balance with the normal force from the floor (equal to the body weight) and the muscle force transmitted by the Achilles tendon on the calcaneus (heel). (The mass of the foot itself

= 1 λu,leg L3u,leg 3 (3.34) where λu,leg = mu,leg /Lu,leg = 0.62mleg /0.46Lleg = 1.34mleg /Lleg and λl,leg = ml,leg /Ll,leg = 0.38mleg /0.54Lleg = 0.70mleg /Lleg . With Lu,leg = 0.46Lleg , we see that I = 0.256mleg L2leg . (Problem 3.17 compares these models of the moments on inertia with measured data, using the parallel axis theorem and the radii of gyration in Table 1.9.) Then ω = (mleg gd/I)1/2 = (mleg g(0.421Lleg )/(0.256mleg L2leg ))1/2 = (1.64g/Lleg )1/2 . We see that Thalf period =

(3), severe injury (4), critical injury (5), and to unsurvivable injury (6). There are semiquantitative guidelines for the severity and likely fatality of head injuries that have been determined from the records of past accidents [119, 156]. Using data from experiments on cadavers and animals, the Wayne State University Concussion Tolerance Curve was developed [124, 125, 143], which Gadd converted into an index [120]. The Gadd severity index (GSI) is defined as GSI = adecel g 2.5 dt, (3.103)

record pole vault (6.14 m) exceeds that calculated here (5.4 m). Compare this world record to the calculation assuming world class speed, 10.2 m/s, and hmin = 0.02 m. Why are they different? 3.34. In a high jump the athlete takes a running start and then hurls himself over a horizontal pole. (In the older, straddle high jump (face down when over the bar), the athlete’s center of mass is ∼150 mm over the bar, while in the newer Fosbury flop method (face up when over the bar), the center of mass is

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