Kinematics is the branch of physics responsible for mathematically describing motion . To achieve its objective, kinematics is based on a series of measurements that result in the characteristics of each movement and the type of movement. Thus, the simplest movements are called uniform straights, while the most complex ones are curved.
On the other hand, these movements can be studied from several points of view, but complementary. In the first place , there is the possibility to approach their study analyzing the causes that originated the movement, on the other hand, is the description of the movement from its position, speed and acceleration. This would be the supposed field of study of kinematics, therefore, the reason that gives rise to movement is irrelevant.
The kinematics graphics
One of the most practical ways to get information from a movement and its characteristics is through graphical representation. In this sense, it is possible to differentiate spatial graphs from time graphs. Kinematics
Spatial graphics represent the trajectory of motion, reflecting the positions of the moving point without resorting to time. In contrast, time graphs reflect variation of several magnitudes over time, providing a great deal of information about the characteristics of the movement. Furthermore, the variation of each of these magnitudes expressed in these graphs can also be reflected in its own kinematic diagram.
the relativity of motion
Movement can be defined as the change of position of an object in relation to other fixed objects that are established as a reference.
Following this definition, for kinematics to be able to study the movement, it must previously fix the position of the observer in relation to this movement, so that the same body can be at rest or in movement according to the position of the observer.
An example of this is the case of an airplane passenger who is inside the aircraft. As the plane takes off it rests in the same way there is movement on the runway. Another case occurs when a ball is thrown in the corridor of a moving train, thus, there is a movement with different characteristics, from the perspective of the observer who is on the platform or inside the same train.
Therefore, the states of rest or motion of a body cannot be classified as absolute, but relative, depending on the frame of reference of the observer.