Do you think that lying in your bed, you do not move?
Regarding the floor and walls in the bedroom - yes. But you move like a point on a circle in the daily rotation of the earth.
And fly around the sun with the planet.
And at night the flight speed is higher than in the daytime, due to the greater distance to the whole diameter.
What is the relativity of motion
If in the calm weather waking up in the cabinSailing yacht, the passenger looks out the window, he does not immediately realize - the ship is floating or lying in a drift. Behind the thick glass there is a monotonous surface of the sea, above - a heavenly blue with fixed clouds. However, in any case the yacht will be in motion. And more than that - just in several movements with respect to different frames of reference. Even without taking into account the cosmic scale, this person, being in a state of rest relative to the hull of the yacht, is in a state of motion relative to the surrounding mass of water. This can be seen on the wake of the jet. But also in the event that the yacht drifts with the sail down, it moves with the water flow forming the sea current.
Thus, any body that is at rest relative to one body (frame of reference) is simultaneously in a state of motion relative to another body (another frame of reference).
Principle of Galilean Relativity
On the relativity of the movement alreadyMedieval scientists, and in the Renaissance, these ideas have been further developed. "Why do not we feel the rotation of the Earth?" - thinkers wondered. A clear formulation based on physical laws relied on the principle of relativity Galileo Galilei. "For objects captured by a uniform movement," the scientist concluded, "this latter does not exist, as it were, and manifests its effect only on things that do not take part in it." True, this statement is valid only within the laws of classical mechanics.
Relativity of path, trajectory and speed
Traversed path, trajectory and velocity of the body orThe points will also be relative, depending on the selected reference frame. Take an example with a person walking through the cars. His way for a certain period of time with respect to the composition will be equal to the distance traveled by his own feet. The path relative to the earth will be composed of the distance traveled by the train and the distance traveled directly by the person, and, regardless of the direction in which it traveled. Same with speed. But here the speed of the person's movement relative to the earth will be higher than the speed of the train - if a person goes along the train's movement, and lower - if it goes in the opposite direction.
The relativity of the trajectory of the point is convenientTrack on the example of a nut attached to the rim of the bicycle wheel and holding the spoke. Relatively to the rim, it will be immovable. Regarding the body of the bicycle - this will be the trajectory of the circle. And with respect to the earth, the trajectory of this point will represent a continuous chain of semicircles.