Uniform rectilinear motion: concept and basic characteristics
Uniform and uneven motion arethe most important concepts of kinematics. The main point of this section of physics is that, considering the translational motion of a body, it should be borne in mind that all its points move in the same direction with an absolutely identical speed. That is why it is not necessary to give a characterization of the motion of the whole given body, we can confine ourselves to just one of its points.
To the main characteristics of any movementinclude its trajectory, displacement and speed. The trajectory is just a line existing only in the imagination, along which the movement of a given material point in space takes place. The displacement is a vector directed from the initial point to the final point. Finally, speed is a general indicator of the motion of a point that characterizes not only its direction, but also the speed of movement relative to any body taken as the reference point.
Uniform rectilinear motion is in many ways an imaginary concept, which is characterized by two main factors - uniformity and straightforwardness.
Evenness of movement means that itis carried out at a constant speed without any acceleration. The straightness of the movement implies that it occurs along a straight line, that is, its trajectory is an absolutely straight line.
Based on all of the above, you can dothe conclusion that uniform rectilinear motion is a special kind of movement, as a result of which the body performs the same movement in absolutely equal intervals of time. So, having broken a certain interval into equal intervals (for example, one second each), one can see that with the above motion the body will pass the same distance for each of these segments.
Speed of uniform rectilinear motionis a vector quantity that in numerical expression is equal to the ratio of the path traversed by the body for a particular time interval to the numerical value of this interval. This value does not depend on time in any way, moreover, it is worth noting that the speed of uniform rectilinear motion at any point of the trajectory coincides absolutely with the displacement of the body. In this case, the quantitative value of the average velocity for an arbitrary time interval taken is equal to the instantaneous velocity.
Uniform straight motioncharacterized by a special approach to the path that passes the body for a certain period of time. The passed way with this kind of movement is nothing more than a displacement module. The movement, in turn, is the product of the speed with which the body moved, for the time during which this movement was carried out.
It is only natural that if the displacement vectorcoincides with the positive direction of the abscissa axis, the projection of the calculated velocity will not only be positive, but also coincide with the magnitude of the velocity.
Uniform rectilinear motion can be represented, including, and in the form of an equation in which the relationship between the coordinates of the body and time will be reflected.