To the physical quantities, classified as vector and scalar, contribute to the description of physical phenomena, being represented by their value followed by their unit of measurement correspondent, standardized by the international system of units.
Read too: What is order of magnitude?
Summary of physical quantities
Physical quantities are written by a numerical value and a unit of measurement.
they can be scalar or vector.
Scalars have no magnitude, direction and sense, just a numerical value.
Vectors have magnitude, direction and sense.
There are several physical quantities, such as time, mass, force, magnetic field.
We use measurement units to measure them.
What are physical quantities?
the physical quantities characterize physical phenomena by measuring, either quantitatively or qualitatively. They are symbolized by a numerical value together with their unit of measurement.
Types of physical quantities
Physical quantities can be classified into vectors and scalars. The best way to tell them apart is to assess whether or not they need guidance about their meaning or direction.
vector quantities
It is the magnitudes that need information about their orientation and module to be understood. For example, speed is a vector quantity, since it is necessary to know where the car is going, for example.
scalar quantities
They are the magnitudes that, in order to be assimilated, only numerical value is enough. For example, time is a scalar quantity, since it is unnecessary for us to know where it is going, because, in this case, there is only direction and direction.
What are physical quantities?
There are several physical quantities, below we can see some of them:
Distance: quantity that measures the interval between two moments.
Length: extension between two endpoints in a single dimension.
Amplitude: maximum range of a vibration relative to the equilibrium point.
Area: measurement of the surface of an object.
Volume: measure of the space an object occupies.
Speed: variation of distance by time.
Acceleration: change in speed over time.
Time: duration of an event, fact.
Pasta: matter concentration.
Strength: ability to overcome inertia by generating movement.
Electric field: field around the electric charges or electrified surface.
Magnetic field: region that exerts forces on electrical charges and/or magnetic materials.
Magnetic inductance: tendency of a conductor to oppose the change of electric current.
electric charge: physical property originating from subatomic particles.
Electric potential: change in energy as a function of time.
Electric current: flow of electric charge in a time interval.
electrical resistance: ability to resist the movement of electrical charges.
Capacitance: amount of electrical energy that can be stored by a given voltage.
Power: amount of energy consumed or released during a period of time.
Energy: innate transference that results in the performance of work.
Work: effort to move an object with a given force.
Quantity of heat: energy in thermal form.
Temperature: level of agitation of the molecules.
Pressure: force applied to an area.
Voltage: strength of traction exerted on a cable, rope.
Frequency: number of oscillations of an event.
measurement units
As we have seen, physical quantities are symbolized by a numerical value and its unit of measure, so that the units of measure are used to specify which physical quantity we are working with, for example, in the case of the quantity length, we use the meter unit. They are standardized by the International System of Units (SI), facilitating the study of physics, so, for example, the kilogram of rice in Goiás is the same in São Paulo.
Table with physical quantities and their units
Below, some physical quantities represented with their type and unit of measurement according to the SI.
Greatness |
Type |
Unit of measurement |
Representation of the unit of measure |
Distance |
Vector |
Subway |
m |
Length, breadth |
Climb |
Subway |
m |
Area |
Climb |
Square meter |
\(m^2\) |
Volume |
Climb |
Cubic meter |
\(m^3\) |
Speed |
Vector |
meter per second |
\({m}/{s}\) |
Acceleration |
Vector |
meter per second squared |
\({m}/{s^2}\) |
Time |
Climb |
Second |
s |
Pasta |
Climb |
Kilogram |
kg |
Strength |
Vector |
Newton |
No |
Electric field |
Vector |
Newton by Coulomb |
N/C |
Magnetic field, magnetic inductance |
Vector |
Tesla |
T |
electric charge |
Climb |
Coulomb |
W |
Electric potential |
Climb |
Volt |
V |
Electric current |
Climb |
Ampere |
A |
electrical resistance |
Climb |
Oh M |
\(\Omega\) |
capacitance |
Climb |
Farad |
F |
Power |
Climb |
Watt |
W |
Energy, work, amount of heat |
Climb |
Joule |
J |
Temperature |
Climb |
kelvin |
K |
pressure, tension |
Climb |
Easter |
Shovel |
Frequency |
Climb |
hertz |
Hz |
See too: How to identify inversely proportional quantities?
Solved exercises on physical quantities
question 1
(UEPG - PR) When we say that the velocity of a ball is 20 m/s, horizontal and to the right, we are defining the velocity as a quantity:
A) climb
B) algebraic
C) linear
D) vector
Resolution:
Alternative D
Vector quantities have magnitude and direction, so velocity is a vector quantity.
question 2
(UnB) All of the following physical quantities are scalars EXCEPT:
A) mass of the hydrogen atom
B) time interval between two solar eclipses
C) weight of a body
D) density of an iron alloy
Resolution:
Alternative C
The weight of a body, in fact, is about the strength weight, a vector quantity.
By Pamella Raphaella Melo
Physics Teacher
Source: Brazil School - https://brasilescola.uol.com.br/fisica/grandezas-fisicas.htm
