Mechanics, Heat, and the Human Body
Editorial Reviews
Book Description
PREFACE In writing this book, I had the goal of providing an introduction to physics for those students who are particularly interested in the human body. On the basis of my many years of teaching physics to premedical, physical therapy and occupational therapy students, I set these guidelines: The text would cover a limited number of distinct physics topics rather than providing an encyclopedic survey of the field of physics. These topics would be illustrated (examples and problems) with reference to specific functions and characteristics of the human body. The material would be covered in greater depth than is typical of an introductory text. This provides an opportunity to demonstrate the roles that physics. and mathematical analysis play in understanding the body. The examples and problems would span a range from straightforward applications of basic physics principles to those requiring significant analysis. My students have, during the past five years, used the notes on which the text is based as a standalone text for a one-semester course. Much of the present content is based on their questions, criticisms, and suggestions. For example: The discussion of each topic is built around a series of steps on which the analysis is based. Both the SI and USA (English) systems of units are used in the book. Although the SI system is the legal system in this country and is the most commonly used system in the sciences, it is not widely used outside of those fields. Therefore, most students are much more familiar with the USA system, and this familiarity is addressed by inclusion of the USA system. The various tables indicate sources of the data in the bibliography. Answers to all of the quantitative problems are included. I strongly suggest that students who use this book do not limit their efforts to reading it. To derive the full benefits that I hope are present, it is necessary that during your reading, you fill in any gaps between equations. There should be no "magic," no material that seems to come from nowhere. Do as many problems as your time allows. In your analyses of these problems, follow the suggested procedures rather than using shortcuts. Each analysis should include the basic applicable physics principle and clearly show how it is used. The answers to all problems are given. Do not work from these answers backward to produce your analysis. Such an approach is self-defeating because you will not be given the answers on exams or if you enter a field in which you must carry out such analyses. One last comment: This text is intended to be a physics book, not an anatomy or physiology text. The human body is extremely complex, and to deal with its functions at an introductory level, many simplifications have been made. Modeling is employed; for example, muscles are treated as if they are simple line forces. Nevertheless, the results of the analyses are illustrative of the body's functions. I look forward to your comments and questions regarding the book. Please contact me via e-mail at goldick@mail.hartford.edu. INTRODUCTION Our understanding of the human body and the means by which we deal with maladies and injuries have undergone amazing changes during the last 100 years. Illnesses that had been viewed as the result of Divine Intervention are now viewed in terms of the effects of bacteria and/or viruses. Amputation was a common medical response to severe trauma to limbs but is now very rare. The field of prosthetics has advanced to such a degree that those who have lost limbs are no longer doomed td living a marginal life but may now lead so full a life that it is sometimes difficult to realize that they have such a handicap. In the past, a person who had suffered a spinal cord injury that resulted in loss of the use of his or her legs could look forward only to life in a wheelchair. A person suffering that injury today can reasonably hope to walk and even climb stairs. Whereas exploratory surgery was common in the past, it is now very rare, having been replaced by noninvasive means. These and many other medical advances testify to the central role that the physical sciences and technology play in our dealings with the human body. In this text, we will deal with the application of certain aspects of physics (mechanics and heat) to the human body. We will answer questions such as the following: If a 150-pound woman were standing while holding a 10-pound child, how much force would be acting to compressing her lower back? (About 109 pounds) She bends over to put the child down into a playpen. How much force is now compressing her lower back? (439 pounds) (See page 109.) Why does a person who has injured his right hip lean toward his right when walking? Why should he use a cane on his left rather than his right side? (See pages 113-115.) What is the average power output of a catcher while stopping a fastball? (5 hp) (See page 146.) How many times would you have to curl an 11-pound weight to burn off the energy you take in by eating six chocolate chip cookies? (5000) (See page 171.) You know that your body produces heat when you exercise. How does the rate at which your body produces heat compare to the rate at which a 100-watt lightbulb produces heat? Surprisingly, even when you are not exerting yourself, as while lying still in bed, you are producing heat at a rate comparable to that of the lightbulb. (See page 148.) Why does your body seems to produce and retain fat so easily, and why is it so difficult to lose the fat? (See page 150.) What is the function of kneecaps? (See page 192.) Why is your spinal column curved rather than straight? (See page 97.) Why does a pregnant woman usually lean backward when standing? (See page 97.) How is it possible for a cold-blooded animal such as a tuna or a shark to have an internal temperature that is higher than that of the cold water in which it swims? (See page 188.) As we learn how to analyze these and many other situations, we will become familiar with concepts that are basic to physics, such as Newton's laws and conservation of energy. We will also learn about the anatomy and physiology of the human body; in particular, we will deal with the muscular-skeletal system, digestion, and temperature regulation systems. Perhaps more important than this information, which can be found in many books, is the techniques of analysis and quantitative reasoning that we will develop. In my opinion, it has been the application of these techniques that has made possible the amazing advances in medicine and health care in general that we enjoy today. HISTORICAL BACKGROUND Our efforts to understand or explain the world seem to be inherent. Evidence for this statement comes from such diverse areas of study as comparative mythology and child psychology. Just as a child repetitively asks "Why?" and seems never to be satisfied by the answers, so it was with our ancestors. Unfortunately, this attitude is not supported by contemporary culture and has been replaced by a sort of sophistication and noncritical collective agreement characterized by "OK?" "Sure." Try to imagine a culture where the interchange would be "OK?" "No, explain it more clearly." That is the culture that our studies will represent. Our studies will deal with the human body. How do we come to understand the body? This has been a long and difficult process. As we shall see, there were many questions that we would consider to be perfectly legitimate but that were, for many hundreds of years, the province of religion rather than science. There are many obvious questions about the body that must have been raised recurrently since time immemorial. Such questions as "Where do babies come from?" "Why do people die?" "How can I get rid of this cold?" "How can I get rid of this headache?" are ancient; many of them have only recently been answered, and some of them still do not have definitive answers. I remember attending an exhibit of cave art at the Metropolitan Museum of Art in New York City several years ago. The exhibit consisted of artifacts and reproductions of drawings that had been found in caves in France and Spain. These represented the artistic accomplishments of people who lived approximately 40,000 years ago. As I examined the exhibit, I noticed that although there were many female fertility symbols small statues of female figures emphasizing breasts, hips, and bellies there were no male fertility symbols, that is, phallic symbols. I asked an attendant whether the exclusion had been purposeful and was directed to an animal's horn that had been decorated with drawings. Still curious about the relative abundance of female symbols and scarcity of male symbols, it came to me that perhaps these artifacts dated from before the time when people realized that the male had anything to do with making babies. The role of the female is obvious, but who could remember and associate with the birth an activity that had happened nine months earlier? No wonder that conception and birth were viewed as mysterious events, playing a central role in mythology and religion. As with conception and birth, so too with disease and death. It seemed to early people that one could divide concerns about the body into two categories: those that were inherently mysterious, such as conception, death, and disease, and those that were directly observable and hence understandable, such as wounds. It became accepted that while the former were to be dealt with through religion and other spiritual that is, nonphysical means (see the Book of Job), the latter situations were amenable to human intervention, such as stopping bleeding and setting broken bones. This separation was widely accepted through the eighteenth century. Today, most people accept the physical, as opposed to spiritual, bases of birth, death, and disease. This change has affected human perception to such a degree that when there is no quick, effective intervention for such maladies as the common cold and AIDS, some people find it easier to believe that there is a conspiracy rather than a lack of scientific kn...
Book Info
Univ. of Hartford, CT. Basic physics textbook for students in physical and occupational therapy. Emphasizes physics principles as they relate to the human body. Features: examples and problems, topics developed quantitatively using high-school-level algebra, and SI and USA systems of units used throughout. Halftone illustrations. Softcover.
Mechanics, Heat, and the Human Body
Mechanics, Heat, and the Human Body,Howard D. Goldick,Prentice Hall,0139228160,Allied Health Services - Occupational Therapy,Allied Health Services - Physical Therapy,Biophysics,Biophysics (General),Heat,Human mechanics,Life Sciences - Biophysics,Mechanics,Medical / Nursing,Physical Medicine & Rehabilitation,Physics,Physiology,Science,Science/Mathematics,Physiotherapy,Rehabilitation,Science / Physics
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