Mechanics is a part of physics in which mechanical motion of material bodies is studied. Mechanical motion means change in the position of a body or its parts in space over time.
Mechanics based on Newton's laws is called classical mechanics. It deals with motion of macroscopic bodies at velocities much less than the velocity of light in free space.
The subject matter of this section can be of interest for the following reasons:
• understanding mechanics of motion of the whole body for purposes of sports and space medicine, mechanics of a human musculoskeletal system for purposes of anatomy and physiology;
• learning about mechanical properties of biological tissues and fluids;
• understanding the ear and vestibular apparatus operation as physical devices, the heart as a pump, etc.;
• explanation of the biophysical mechanism of action of ultrasound;
• understanding physical fundamentals of some laboratory techniques used in practice of biomedical research, e.g., centrifugation.
Chapter 5 Mechanics of rotational motion
Observing complex movements, such as the movement of a human body (walking, running, jumping, etc.), it seems difficult or even impossible to describe motion of all its points. However, analyzing such movements, it can be seen that they consist of simpler ones - translational and rotational movements.
The reader already knows the mechanics of translational motion, so the section begins with consideration of rotational motion. The simplest one is rotation of a solid body about the fixed axis. This case makes it possible to familiarize yourself with the specific character, terminology, and laws of rotational motion.
§ 5.1. KINEMATICS OF ROTATIONAL MOTION OF A PERFECTLY RIGID BODY ABOUT A FIXED AXIS