Physics

It is the science that studies the nature and matter. Also, it observes physical changes produced in nature. Physics comes to discover the laws by wich these changes happened.



Physical phenomenon

They are the changes produced in sustances and not alter their composition. In physical phenomenon can change some properties like the volume or temperature.
An example of phisical phenomenon are changes of state.



Physical magnitudes
It is a group of properties of a body with a amount . Therefore, it can be measured. There are two trips of physical magnitudes:

> Scalar magnitudes: are the magnitudes defined by a numerical amount. For example, the temperature, mass...
> Vector magnitude: are the magnitudes defined when we show their module, sense and direction.
For example, the force, speed..


Vector
It is a segment ( line) that only represents scalar magnitudes because they are defined by their differents elements.
A vector needs:


  • Module is the length of the vector. The length of the segment.
  • Direction, the direction of the vector is defined by the line that contains the vector.
  • Sense is defined by the arrow of the vector.


external image vector%20%281%29.jpg




Motion;

Motion refers when a body or object with respect to a fixed point it changes its position. And object is in motion when adopted a different place over the time.

The motion is make up by three parts: path position and displacement.



Reference system
It is the point or a set points by means of which describe the motion of a body. The motion relative, we can say that a body is in movement with respect to our reference system. If we take like fixed point other different the body can be at rest.



Path
It is the line formed by the several point by passing a body in his travel.
In more specific,words: line described by successive positions defined by a body in his motion.
The path depends of reference system, fixed point by who looks. Path can be rectilinear, when the line which describe it it's a recta, or curvilinear, when it's a curve.




Position
It is the distance of system of reference.



Displacementent
It is the change of position of a body, with respect, a fixed point. That is to say the path that defines the position of a body.


Speed; it is a physical magnitude that expresses the distance covered by a body in a amount of time. It can be calculate two sorts of speed:

>Average speed, it is the relation between the distance travelled and time spent.
Pantallazo-8.png


> Instantaneous speed, it is the velocity in particular moment. It's the speed that you take in an instant. For example the velocity indicated by the speedmeter of the car.



Acceleration
It is a vector magnitude that indicates the changes of velocity over the time.


> Average acceleration, it is the relation between the veocity and the time spent.

Pantallazo-9.png


> Instantaneous acceleration,it is the change of velocity in a particular moment. It's the acceleration that you take in an instant.




MRU ( Rectilinear Uniform Movement)

It is the movement with the vector velocity remains constant, so module, sense and direction are constant.


X= X0 + V(t-t0)


Example: A cyclist that cover some spaces in some times.

Sin_título.png



MRUA ( Uniformily Accelered Rectilinear Movement)

It is the movement which an object is travelling on a straight line when the acceleration remains constant.

Pantallazo-2.png

Example, an airplane that moves an starts to accelerate until reach , 100m/s of velocity.


Sin_título-1.png



MCU (Uniform circular motion)

It is the movement wich path isn't speed a straigth line, is a circle with constant angular speed. In this movement, the module of vector speed is constant but the direction changing all the time.

Example: the turn of a disc in a record player, the movement of a booth of bigwheel.


Pantallazo-10.png

Angular velocity
(ѡ) It is the relation between the angle rotated and time


Pantallazo-3.png



Angular acceleration
(α) It is the result between variation angular velocity and time




System of reference (SR)
It is a spot or group of spots, from whish described the movement.
For example: If we situed in a car in movement, we can see the buildings in movement. The car is our system of reference. But if we situed in a building, we can see the car in movement, the building is our system of reference.




Strength
It is an action be able to change the state of motion, or produced in it some deformation.

For example: The weight.



Newton
It is the meassure of strength. It is the force aplicated in a body that weight 1 Kg, produces an acceleration of 1 m/s2

Sin_título-2.png


For example: When you pick up a book that weight 1 Kg , you produce an acceleration of 1m/s2 , you aplicated in a book a force that 1 N.



Resultant force
It is the total of all the strengths that there are in the system.
For example:



external image 000736606.png




Concurrent forces
They are forces aplicated over lines that they intersect at a point.
For example:



external image vectores+concurrentes.jpg








Parallel force
They are those that have got the same direction but are applied at diferents points.
for example:


external image image013.jpg

Deformation
It is the change on springy or of a body, result to forces applied in here.
For example:



external image fisica_008_01p.gif








LAW OF HOOKE: Hooke said that the deformation on an elastic body is directly proporcional to the applied forces.



Sin_título_3.png

Balance
A body is in balance if:

-Do not exist movement of translation, the resultant force is zero.
-Do not exist movement of rotation, the movement resultant of system of forces is zero.

For example:


Sin_título_4.png



Gravitatory forces
It is the force that exist between two bodies out of they have mass.
LAW OF UNIVERSAL GRAVITATION: Two particles atract each other with a force directly proportional to product od his mass, and inversement propotional to square of distance between they.

Sin_título5.png



Weight
The weight of a body is the force that the Earth atract it.

p= m g







Normal force:










Friction force
It is the force that appears to contact the objectis moving on the surface it moves. Adn it opposses to movement.
For example:
someone who drags a piece of furniture to moved it.


external image 20070924klpcnafyq_146.Ges.SCO.png

Chemistry

It is the science that observes chemical phenomenons produced in nature. Also it mades theories that cans describe the behavior of sustances. chemistry studies the composition and structure of matter, that is to say a deeper study.



Chemical phenomenon
They are the changes produced in substances composition. That is to say, changes that alter their composition. In chemical phenomenons can change specific properties as meeting point.
An example of chemical phenomenon are chemical reactions.