What is Mach?

Ernst mach, an Austrian physicist and philosopher, was one of the founders of empirical criticism. Mach is also short for Mach number. There are also the names of the head coach of China women's basketball team and a network accelerator.

physicist

Ernst mach ernst mach (1838- 19 16) is an Austrian physicist and philosopher. One of the founders of empirical criticism; Mach number and Mach band are also its research results. Mach (ernst mach, 1838 ~ 19 16) is an Austrian physicist, biologist, psychologist and philosopher. 1838 February 18 Born in Chilitz. Father is a tutor. When he was a child, he was good at observing the causal relationship of things with hearing and touch under the charm of nature. When he was in junior high school, he was not interested in the curriculum of missionary schools and was regarded as a child who was not suitable for learning knowledge and had poor grades. His father's library became a treasure house for his self-study. He studied mathematics, physics and philosophy at the University of Vienna, and graduated from 1860 with a doctorate. 1864- 1867 was appointed professor of mathematics and experimental physics at Graz university, 1867- 1895 was appointed professor of experimental physics at Prague university, and was elected president twice. 190 1 year retired, but still continued to engage in scientific writing at home. 19 16 February 19 died in the tester. Mach devoted his life to the research of experimental physics and philosophy. He published more than 100 research papers and reports on mechanics, acoustics and optics. When he studied the high-speed motion of objects in gas, he found the shock wave. The ratio of object speed to sound speed (Mach number) is determined as the standard to describe the supersonic motion of an object. Mach effect, Mach wave, Mach angle and other terms named after Mach are widely used in aerodynamics, which is Mach's historic contribution to mechanics. He first demonstrated the acoustic Doppler effect with instruments and put forward the N-dimensional atomic theory.

mach number

Mach number, named after Austrian physicist Mach (1838- 19 16), is defined as the ratio of the speed of an object to the speed of sound, that is, the multiple of the speed of sound. Among them, there are many kinds of Mach numbers, such as the flight Mach number used by aircraft in the air, the airflow Mach number of airflow speed, the local Mach number of a certain speed in complex flow field and so on. Because Mach number is the ratio of speed to sound speed, and sound speed has different values at different altitudes, temperatures, etc., it is impossible to convert the value of "M2.8" into units such as km/hr or mph, and Mach number cannot be used as a speed unit. The biggest function of Mach number is to distinguish subsonic speed less than 0.8 times the speed of sound, transonic speed 0.8~ 1.2 times the speed of sound, supersonic speed 1.2~5 times the speed of sound and hypersonic speed above 5 times the speed of sound.

Tom maher, translated by Tom Mayer. The head coach of China women's basketball team was born on September 4th, 1952, and was announced by chinese basketball association on March 6th, 2005. His term of office was fixed until the end of the 2008 Olympic Games.

Mach 5 is a famous network accelerator.