In political science, a revolution (Latin: revolutio, “a turn around”) is a fundamental and relatively sudden change in political power and political organization which occurs when the population revolt against the government, typically due to perceived oppression (political, social, economic). In book V of the Politics, the Ancient Greek philosopher Aristotle (384–322 BC) described two types of political revolution:
- Complete change from one constitution to another
- Modification of an existing constitution.
Revolutions have occurred through human history and vary widely in terms of methods, duration and motivating ideology. Their results include major changes in culture, economy and socio–political institutions, usually in response to perceived overwhelming autocracy or plutocracy.
According to the International System of Units (SI), rpm is not a unit. This is because the word revolution is a semantic annotation rather than a unit. The annotation is instead done as a subscript of the formula sign if needed. Because of the measured physical quantity, the formula sign has to be f for (rotational) frequency and ω or Ω for angular velocity. The corresponding basic SI derived unit is s−1 or Hz. When measuring angular speed, the unit radians per second is used.
Formally, hertz (Hz) and radian per second (rad/s) are two different names for the same SI unit, s−1. However, they are used for two different but proportional ISQ quantities: frequency and angular frequency (angular speed, magnitude of angular velocity). The conversion between a frequency f (measured in hertz) and an angular velocity ω (measured in radians per second) are:
Thus a disc rotating at 60 rpm is said to be rotating at either 2π rad/s or 1 Hz, where the former measures the angular velocity and the latter reflects the number of revolutions per second.
If the non-SI unit rpm is considered a unit of frequency, then 1 rpm = 1/60 Hz. If it instead is considered a unit of angular velocity and the word “revolution” is considered to mean 2π radians, then 1 rpm = 2π/60 rad/s.
rev·o·lu·tion | \ ˌre-və-ˈlü-shən \
Definition of revolution
1a(1) : the action by a celestial body of going round in an orbit or elliptical course also : apparent movement of such a body round the earth
(2) : the time taken by a celestial body to make a complete round in its orbit
(3) : the rotation of a celestial body on its axis
b : completion of a course (as of years) also : the period made by the regular succession of a measure of time or by a succession of similar events
c(1) : a progressive motion of a body around an axis so that any line of the body parallel to the axis returns to its initial position while remaining parallel to the axis in transit and usually at a constant distance from it
(2) : motion of any figure about a center or axis revolution of a right triangle about one of its legs generates a cone
(3) : rotation sense 1b
2a : a sudden, radical, or complete change
b : a fundamental change in political organization especially : the overthrow or renunciation of one government or ruler and the substitution of another by the governed
c : activity or movement designed to effect fundamental changes in the socioeconomic situation
d : a fundamental change in the way of thinking about or visualizing something : a change of paradigm the Copernican revolution
e : a changeover in use or preference especially in technology the computer revolutionthe foreign car revolution