TY - CHAP M1 - Book, Section TI - Kinematics A1 - Sims, Carrie A. A1 - M. Reilly, Patrick A2 - Feliciano, David V. A2 - Mattox, Kenneth L. A2 - Moore, Ernest E. PY - 2020 T2 - Trauma, 9e AB - KEY POINTSA body in motion stays in motion, moving at the same speed and direction, unless acted on by a force.The energy of an object and its potential to do damage are directly proportional to its mass and the square of its velocity .The total energy of a system cannot be destroyed, although it may be transferred between objects or transformed into work.All injuries can be explained by four different types of strain (tensile, shear, compressive, and/or overpressure).If a force causes a decrease in the original volume of a fluid- or air-filled structure, there must be a concomitant increase in the pressure.The shape (and thus the sectional density) of a bullet is subject to change within the tissue and directly impacts the degree of tissue damage.A projectile creates both a permanent cavitation or “bullet track” and a hydrostatic pressure wave that stretches and damages adjacent tissues.In explosions, more energy is transferred if the shock wave travels through a medium of similar density (eg, water and the human body). SN - PB - McGraw Hill CY - New York, NY Y2 - 2024/04/19 UR - accesssurgery.mhmedical.com/content.aspx?aid=1175129870 ER -