Rotational movement involves a change in orientation that occurs in a specific way, which causes a line or point to remain unchanged.
A rotation movement is a modification of orientation that is generated in a certain specific way, which causes a point or a line to remain unchanged.
It should be noted that moving consists of making an object leave one place and occupy a different one . The verb also refers to shaking something . Motion , therefore, is the state of objects at the moment they move.
On the other hand, rotation - from the Latin rotatio - is a concept linked to the verb to rotate , which means to make turns around an axis.
About rotation movement
Rotational motion can be represented by a vector that is located above the axis of rotation . If said axis passes through the center of gravity of the body, it will rotate on itself. The rotation, however, can be oscillatory.
The complete rotation of a body about its own axis is known, in the field of mechanical engineering, as a revolution . For astronomy, a revolution is an orbital-type movement of translation of one star around another.
Planet Earth performs a rotation movement.
The behavior of the Earth
We can understand what a rotation movement is from the behavior of planet Earth . Our planet has an ellipsoid shape, with flattened poles, and develops four main movements (known as nutation , precession , translation and rotation ). In the case of rotation movement, it consists of the rotation that the Earth makes on itself along the terrestrial (imaginary) axis that crosses the poles.
It is worth mentioning that this is not an exclusive characteristic of the Earth, but that any celestial body present in space and suspended by gravitational effect performs a wide variety of movements. In this case, our planet takes 23 hours, 56 minutes and 4 seconds to rotate on its axis, to make a complete turn and form what is called a sidereal day . An astrophysicist from France named Foucault carried out an interesting experiment to support the theory of the rotational motion of the Earth; To do this, he used a pendulum, which he held above an illustration of the cardinal points. Through this test he was also able to maintain the veracity of the translation around the Sun in orbit.
Given that our planet does not have a completely symmetrical or rigid shape and that the force exerted by its gravitational field has a certain influence on the other elements of the galaxy , the movements it makes can be detected in relation to the passage of time. In fact, in a not-so-remote time the Earth's rotation was used to measure time, based on the fact that its speed was constant, so that any sample taken would allow for consistent results to be obtained.
Later it was discovered that the Earth does not rotate on its own axis at a constant speed, but rather varies following different patterns , which have been identified with the names:
- Secular , when due to the increase in sea friction the time it takes to make a complete turn increases linearly, resulting in days lasting between 0.0005 and 0.0035 seconds longer for each century that has passed.
- Irregulars , which have extended the length of days by approximately 0.01 seconds over the last 200 years.
- Newspapers , products of processes that are repeated cyclically and that impact the Earth, such as the gravitational action of the Moon on the oceans; In these cases, the variations reach a reduction of 0.0005 seconds in just over a year.