Imagine that you are sitting at a bus stop and soon notice that transport is approaching. As the driver is inside the bus, he and all passengers approach you. Soon, we then realize that the whole: bus, passengers and driver, is moving.
People who are on the bus do not notice the driver or moving away or approaching, for them (passengers) the driver is quiet, that is, he is at rest.
We see then that for the same simultaneous event the conditions of movement and rest are relative and depend on who observes them.
Do this: lie on your bed and be still. Now ask yourself the following question: Am I moving or at rest? If you answer the question about the bed you're lying on, you're sure to be at rest. Now imagine that there is an observer in the Sun and from there he sees you lying in your bed; as the Earth revolves around the Sun and you are on the Earth, it will soon sense you in motion.
We see then that for a given body to be in motion, its position must change over time with respect to an observer; and for a given body to be at rest, its position must not change over time with respect to an observer.
When we choose an observer to determine and identify the state of rest or movement of a body, we are establishing the frame or reference system in which an event will be analyzed.
It is concluded that movement and rest are relative, that is, they depend on the adopted reference system.
Bus driver, the frame determines your state of motion or rest.
By Frederico Borges de Almeida
Graduated in Physics
Brazil School Team
mechanics - Physics - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/fisica/referencial-movimento-repouso.htm
