What is the movement?

We explain what the movement is and the categories in which it can be classified. In addition, the elements that compose it and examples.

1. What is the movement?

In physics , movement is understood as the change of position that a body experiences in space , taking into consideration time and a reference point where the observer of the phenomenon is located. That is to say, that the characteristics of any movement will depend on the reference system, that is, on the point of view from which it is viewed

According to this reference system, the equations used to calculate the characteristics of a given movement will vary. In some of them the direction of the movement (vector equations) is taken into account, while in others it is enough to attend to its particularities, such as speed, acceleration and distance traveled.

The movement has been studied since ancient times, and caught the attention of the great Greek and Roman philosophers. Since then this study  tends to represent the movement through graphs , taking into account the particularities of the equations used to describe it.

Currently, the branch of physics that studies movement is kinematics , but also dynamics . However, the one in charge of postulating the laws of the operation of this phenomenon was mechanics , in its three aspects: classical (or Newtonian), relativistic and quantum.

2. Movement types

According to the type of trajectory that a mobile describes, the movement can be classified into the following categories:

• Rectilinear movement . The one whose trajectory describes a line, and in which the speed and acceleration are always parallel. It is usually studied in two specific cases:
  • Uniform Rectilinear Movement  . It has a constant speed, with zero acceleration.
  • Uniformly accelerated Rectilinear Movement  . The mobile has a constant acceleration, that is to say, that at any moment of the route it will always be the same, since the speed always increases or decreases at the same rate .
• Circular movement . It has an axis of rotation and a constant radius with respect to it, thus drawing a perfect circumference. If its angular velocity is constant, in addition, we will be in the presence of a uniform circular motion, but usually this type of movement has a margin of acceleration.
• Wave motion . It is the combination of two movements: one horizontal uniform rectilinear and another uniformly accelerated vertical rectilinear. The result is an undulating path, just like that of sound waves through the air .
• Parabolic movement . He who draws a parabola, that is, the result of the composition of a uniform horizontal rectilinear motion and a uniformly accelerated vertical. This considering that a parabola is a cut in a certain wave .
• Pendulous movement . The movement traced by pendulums, whether simple, twist or physical pendulum.
• SHM . Also called simple harmonic vibratory motion, it is the one presented by springs and other objects whose movement is periodic and is described in time by a harmonic function (sine or cosine).

3. Elements of the movement

The elements of the movement are its characterizations or describable properties, and are the following:

• Path . The line with which the movement of a specific body can be described, and which according to its nature can be:
  • Rectilinear . When it is a straight line without variations in its trajectory.
  • Curvy . When drawing a curved line, that is, a circle fragment.
  • Circular . When you draw a full circle in your walk.
  • Elliptic . When you trace a fragment of an ellipse or a complete ellipse.
  • Parabolic . When he describes a parable in its displacement.
• Distance . The amount of space traveled by the mobile in its displacement .
• Speed . It is the relationship between the distance traveled and the time the mobile does it. That is to say: the faster the speed, the more distance per unit of time a body travels, and vice versa.
• Acceleration . The variation of the speed (comparing the initial speed and the final speed) per unit of time experienced by a mobile whose displacement is not uniform. If the acceleration is positive, speed is gained; If it is negative, it is lost.

4. Examples of movement

In many cases the movement is studied in ideal terms, but in other cases there are many everyday examples to illustrate them, such as:

• The movement of the stars . The planets revolve around the sun in elliptical orbits, that is, tracing a uniform elliptical motion that can well be calculated and examined.
• The pendulum of a clock . The clocks of yesteryear worked based on the movement of a pendulum to mark the seconds. This movement is the perfect example of the simple pendulum movement, which is the same as we use in movies to “hypnotize” someone.
• A bowling ball  . Since the floor of the bowling courts is waxed to greatly reduce friction, the balls tend to move in uniform rectilinear motion until they hit the pines. However, if we consider from the point where they leave the player’s hand, it will be a uniformly accelerated rectilinear movement, because at rest the speed is zero.