Understanding Relativity and Measurement in Physics

Relativity Law and Phenomena

The relativity law, analyzing phenomena for bodies whose speed is comparable to the speed of light

The time and the space can have a different reference system

Characteristics of Light

The light is reflected and has wave characteristics.

The measurement can be probabilistic and not precisely directs.

Measurement and Physical Magnitude

Measurement: the act of measuring as the comparison of a property or physical magnitude with another of the same class. Assigning a numerical value to the result of said measurement, and adding a unit of measurement which will give us an accurate idea of the physical magnitude that is being measured

Physical Magnitude: is the term associated with some property or characteristic measurable in a certain way, without specifying any numerical value nor any unit of measurement.

Measurement pattern : is to establish the reference with which we will measure we want. To be valid must meet a series of requirements to be used in the world

Physical quantity : is nothing other than the result of measurement, is a numerical value obtained as a result of comparing the physical magnitude of the object to be measured with the corresponding measurement pattern

Physical quantities are the quantifications of the properties that we want to measure, using the instruments designed for that purpose.

Fundamental and Derived Physical Quantities

Are those that do not depend on any other physical magnitude and are measured directly, examples length, mass, time, temperature

Are those that are formed by the combination of two or more fundamental physical quantities, in this case there is a great variety area, volume, speed, acceleration, force, work, power

Measurement Systems

CGS system: It was one of the first established systems in 1832 by a mathematician and scientist Karl Gauss, its fundamental units are: cm gram second

English Units: its origins are in the United Kingdom, the English Units have been replaced little by little by the International System. However, there are many measuring instruments and devices, besides bolts, clothes, shoes, etc. That are measured in these English units, which complicate to convert them to IS. Its fundamental units are: feet pound second

International System: In 1875 Measurement and Weight International Bureau was established in France in order to standardize measuring patterns. Fundamental units of IS were defined through a series of International agreements. The decimal basis is one characteristic of this system. meter kg