Quantities (called magnitudes) combined with direction are called vectors. Quantities not combined with direction are called scalars. A space is a geometry or topology that contains vectors (which may or may not equal a vector space or Euclidean space as defined in mathematics). The kind of a space depends on the units of the magnitude. […]
Here we take the reduced mass and show the parallel reduced vass. In physics, the reduced mass is the “effective” inertial mass appearing in the two-body problem of Newtonian mechanics. It is a quantity which allows the two-body problem to be solved as if it were a one-body problem. Given two object bodies, one with
This continues posts such as the one here related to Aristotle’s four kinds of cause: final cause formal cause efficient cause material cause A subject is a form with purposes. An object is a material with mechanisms. Objects exist with space-time. Subjects exist with time-space. The upper causes apply to subjects, who have final purposes,
In Isaac Newton’s Principia, Definition 1 states: Quantity of matter is a measure of matter that arises from its density and volume jointly. (The Principia: The Authoritative Translation and Guide, Bernard Cohen, Anne Whitman, and Julia Budenz. University of California Press, 2016, p.403) Today density is defined as mass per unit volume, which would make
Since one may associate either the arclength (travel length) or the arctime (travel time) with direction, one might think that the full coordinates for every event are of the form (s, t, ê), with arclength s, arctime t, and unit vector ê. Since the direction is a function of either the arclength or the arctime,
If a stone rolls down a hill, we would say it is simply following the law of gravitation. It is not “going somewhere” as if it had a destination – that would require nature to have a soul, a view that died out in the early modern period. But if a person or an animal or
Previous posts deal with terms for motion, such as here. Further thoughts are below. When someone asks about the length of a trip, they are not asking for the distance between the origin and destination of the trip – that is the magnitude of the displacement. They are asking about the length of the route
The various ways of measuring space and time are parallel. Measuring space: A ruler measures length, that is, the distance between two points (A to B). An ruler turned upside-down measures length backwards (B to A). A tripmeter measures the travel distance of a vehicle trip. An odometer measures the cumulative travel distance. A measuring
Say you’re standing near the bottom of a hill and see a small rock rolling down. How should the motion of the rock be interpreted? It could be that the rock happened to brake loose and roll down the hill. Or it could be that someone took the rock and rolled it down the hill.
This post continues the topic posted here. The action motion of a particle or rigid body may be measured by the scalar (or 1D) rate of motion, expressed as a speed or a pace. The numerator of a speed is the measured length or travel distance, and the denominator is the unit of time or
