Motion

We explain what the movement is and how it is classified. Also, the elements that make it up and some examples.

What is movement?

In physics, movement is understood as change of position experienced by a body in space in a certain period of time. All movement depends on the reference system from which it is observed.

The movement of bodies is studied through kinematics and dynamics and both are integrated into mechanics. Classical mechanics studies phenomena that involve macroscopic bodies with speeds small compared to that of light.

On the other hand, quantum mechanics describes the laws of the behavior of subatomic particles with speeds close to that of light. Finally, the movement of bodies subject to strong gravitational fields is studied within the framework of general relativity.

• See also: Inertia

Types of movement

Depending on the type of trajectory that a mobile device describes, the movement can be classified into the following categories:

• rectilinear movement. Describes a body whose trajectory is linear and with parallel velocity and acceleration. It is usually studied in two specific cases:
  • Uniform Rectilinear Motion. Describes a body that has constant velocity, that is, zero acceleration.
  • Rectilinear Motion Uniformly accelerated. Describes a body that has a constant acceleration.
• uniform circular motion. Describes a body that moves around an axis of rotation, with a constant radius and angular velocity, tracing a circle. In this type of movement, the bodies have an acceleration in the direction of the center of the circle.
• Simple harmonic motion. It describes a periodic movement such as that of a pendulum or that of an electromagnetic wave (light for example). Mathematically it is described in time by a harmonic function (sine or cosine). The movement may not be harmonic, that is, not repeated in time, but still describe wave trajectories and in that case it is called wave motion.
• parabolic motion. Describes a movement that traces a parabola. It is the result of the composition of a uniform horizontal rectilinear motion and a uniformly accelerated vertical motion. An example of this type of movement is that made by a ball that is thrown upwards at an angle with respect to the horizontal.

Elements of movement

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

• Path. It is the line with which the movement of a specific body can be described and which, according to its nature, can be:
  • Rectilinear. Straight line without variations in its trajectory.
  • Curved. Curved line, that is, a fragment of a circle.
  • Circular. Full circumference.
  • Elliptical. Fragment of an ellipse or complete ellipse.
  • Parabolic. Parabolic line.
• Distance. It is the amount of space traveled by the mobile phone in its movement.
• Speed. It is the relationship between the distance traveled and the time in which the mobile travels it (the higher the speed, the more distance a body travels per unit of time).
• Acceleration. It is the variation in speed (final speed minus initial speed) per unit of time.

Examples of movement

Some examples of movements are:

1. The movement of the stars. The planets revolve around the sun in elliptical orbits.
2. 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 one we use in the movies to “hypnotize” someone.
3. a bowling ball. Since the floor of the bowling alleys is waxed to greatly reduce friction, the balls tend to travel in a uniform rectilinear motion until they hit the pins.