The speed of sound Sound waves are longitudinal mechanical waves that can travel through solids, liquids, or gases. The speed of a sound wave in medium(having bulk modulus(容变弹性模量)and density p) is:
Chapter32 Special relativity(狭义相对论) Two Postulates(狭义相对论的两个基本假设) The relativity of simultaneity(同时性的相对性) The relativity of time(时间间隔的相对性) The relativity of length(长度收缩) The Lorentz Transformation(洛仑兹变换式) new look at momentum, energy(相对论质量