Among the variety of motions studied by such a branch of physics as kinematics, there is one in which the body for any arbitrary equal lengths of time passes the same length of the path. This is a uniform movement. An example is the movement of a skater in the middle of a distance or a train on a level stretch.
Theoretically, a body can move along any trajectory, including a curved one. At the same time, there is the concept of a path - the name is the distance traveled by a body along its path. The path is a scalar value and should not be confused with movement. The last term we denote the segment between the starting point of the path and the end, which, when curved, obviously does not coincide with the trajectory. Displacement is a vector quantity that has a numerical value equal to the length of the vector.
A logical question arises - in what cases is it about uniform movement? Will the movement of, for example, a carousel in a circle at the same speed be considered uniform? No, because with this movement the velocity vector changes its direction every second.
Another example is a car traveling in a straight line at the same speed. Such a movement will be considered uniform until the car turns anywhere and the same number on the speedometer. Obviously, uniform motion always occurs in a straight line, while the velocity vector does not change. The path and movement in this case will coincide.
Uniform movement is a movement along a straight path with a constant speed, at which the lengths of the traveled intervals of the path for any equal time intervals are the same. A special case of uniform motion can be considered a state of rest, when the speed and distance traveled are zero.
Speed is a quality characteristic of uniform movement. Obviously, different objects go the same way at different times (pedestrian and car). The ratio of the path traveled by a uniformly moving body to the length of time for which a given path is traveled is called the speed of movement.
Thus, the formula describing uniform motion looks like this:
V = S / t; where V is the speed of movement (is a vector quantity);
S is the path or movement;
t is time.
Knowing the speed of motion, which is unchanged, we can calculate the path traveled by the body for any arbitrary length of time.
Sometimes a uniform and uniformly accelerated movement is mistakenly mixed. These are completely different concepts. Equally accelerated motion is one of the variants of non-uniform motion (i.e., one in which speed is not a constant value), which has an important distinguishing feature - the speed with this type of movement changes over the same time intervals by the same amount. This value, equal to the ratio of the difference in speeds to the length of time during which the speed has changed, is called acceleration. This number, showing how much speed increased or decreased per unit of time, can be large (then they say that the body is rapidly gaining or losing speed) or insignificant when the object accelerates or slows down more smoothly.
Acceleration, as well as speed, is a physical vector quantity. The directional acceleration vector always coincides with the velocity vector. An example of uniformly accelerated motion is the case of free fall of an object, in which the fall velocity (the rate of attraction of the object by the earth's surface) changes per unit time by a certain amount, called the acceleration of gravity.
Uniform motion can theoretically be considered as a special case of uniformly accelerated. Obviously, since the speed does not change during such a movement, acceleration or deceleration does not occur, therefore, the value of the acceleration with uniform movement is always zero.