modern mechanics are several kinds of motion.They differ from each other trajectory, the presence or absence of acceleration, and several other parameters.However, there are also common features: in particular, each type of kinematic actions can be expressed with the coordinate axis.For linear motion trajectory is a straight line, it is clear from its name.We consider this case in more detail.
uniform linear motion - motion, movement characterized by equal distances in the same time intervals.Simply put, for every selected period of time (either 1, 2, 3 seconds or 10 minutes), the body will overcome the distance is absolutely equal to what would be overcome in the next the same time period.Strictly speaking, the ideal linear motion - more abstract model as to achieve such a movement under normal conditions is practically impossible: there are always obstacles.Among them - air resistance characteristics of the moving body and others.
formula of this motion is very simple and is known since the days of high school:
s = v / t,
where s - the distance traveled by the body for a certain period of time, v - speed during the movement, t -the actual time of the distance.It is logical that the rate in such a motion is also constant and unchanging.
uniformly accelerated linear motion - a particular case opisannnogo above with the only difference that here we have a movement with acceleration.The formula for it as follows:
s = Vo + - at2 / 2
Read as: es (distance) equals ve zero (initial speed), plus or minus a (acceleration) Te (time) squared divided by two.A "+ -" it is not delivered by accident.The fact that the linear motion acceleration can be either uniformly accelerated and ravnozamedlennym.The first case corresponds to the formula with a plus, the second - with a minus.Examples: acceleration and braking of the train.In the case where the train speed typing needed and does not need a larger acceleration, it moves at a relatively steady rate, i.e. performs rectilinear motion.
should also consider this type of movement is uneven straightforward.A body moving thus has a speed which can vary without any system, i.e. at any one time.Therefore, it is usually different from the so-called medium speed.PD is uneven from the uniform that speed all the way can be changed (usually in real life we are dealing with such kind of movement).However, to measure the speed at any given point in time is not possible, nor necessary.For this purpose it was introduced such a thing as average speed. Its formula is the same as the formula of speed for uniform PD:
v = s / t,
the only difference is that to find a specific position in a particular point in time is not possible, but you can determine how farIt was completed within a specified time.
Unlike the average, instantaneous velocity with uneven PD - speed, which has the body at any given time.
Now that the specifics of the motion with equal speed is more or less exposed, it is important to clarify and distinguish between straight and curved motion.Given the fact that the linear motion in mechanics almost always means straightforward, it is worth noting: scientists believe that such a move - a special case of curvilinear.Determination of curvilinear motion is: a movement whose trajectory is not a straight matches and curve.Probably due to the fact that the ideal straight path does not exist (just as an abstraction), and what is accepted by us as a straight path - only an approximate value of such, you can really take a view of the curved rectilinear motion.
