The mechanics course at school begins with the concept "uniform motion". This type of the movement the simplest for understanding. It is important to remember that it is a certain idealization which does not meet in real life.
Uniform motion is a simplest type of the movement. That the body moved evenly, its speed has to be same at any moment. It is possible to tell and in a different way: acceleration of a body is equal to zero at any moment. If at all this the body passes identical distances for the same periods, motion is called uniform rectilinear.
Way and movement
Way is called length of a trajectory on which the body during a certain period moved. Movement it is considered to be distance between the initial and final point of a trajectory. Often these concepts confuse, but they designate absolutely different distances. A way - the scalar size, and movement - vector. The module of a vector of movement will be equal to a piece which connects the initial and final point of a trajectory.
Speed of uniform motion
Speed of uniform motion is a vector which module can be calculated easily on the formula known from elementary school. It is equal to the relation of the way passed by a body, at the right time during which this way was passed. It is important to remember that at uniform motion the direction of a vector of speed always has to coincide with the direction of the movement. It is impossible to consider uniform motion on a circle and any curve trajectory. It follows from this that the way and movement at such movement have to be identical. It is easy to learn it from practice. The condition of rest can be carried too to uniform motion as the body for identical periods passes equal distances (in this case they will be just equal to zero). The passable way at uniform motion will consist of two components: initial coordinate and also the work of speed of a body for the period of its movement.
Schedules of uniform motion
If to construct the schedule of change of speed over time for uniform motion, it turns out direct, parallel abscissa axes. The area of a rectangle under this schedule is in number equal to length of the way passed by a body for the set time. Really, the area of a rectangle is equal to the work of its parties (in this case to the work of speed for a while). Having constructed the schedule of dependence of the passable way from time, it is possible to find value of speed with which moves bodies. The schedule has an appearance of the straight line drawn from the beginning of coordinates. The tangent of angle of an inclination of this straight line concerning abscissa axis (time axis) will also be required value of the module of a vector of speed. The more the inclination of the line chart, the has bigger speed a body.