Given the assumptions of classical mechanics, speed characterizes the speed of movement of a point in space.It is a vector quantity, ie, the rate has a direction.Speed is typically measured in kilometers per hour or in meter per second (denoted km / h m / s, respectively).
time in classical mechanics continuously, nothing is determined.To measure used by certain periodic sequence of events, which is considered the standard minimum period of time.This principle is familiar to everyone as an example of ordinary hours.To solve the basic physical problems indicate the time in seconds (s), minutes (m) or hours (h).
distance is the key concept in many sciences.In general terms it can be defined as the degree of removal of the object.In
school physics problems of distance is usually measured in centimeters (cm), meters (m), kilometers (km), etc.
should distinguish between two concepts: the distance between the objects and the distance that the point of overcoming the distance.After all, when you move a point can move along the shortest distance between points, and can, for example, to follow a zigzag path.The distance between the points remain the same, but the way it has done so much more.
Accordingly, different average speed and average speed of movement of the way.For example, for the horse, ran round the racetrack, the average speed of the path is different from zero.While the speed of movement will be zero, as the horse back to the same point from which to move.
It is the average speed of the path is relative to the path traversed by the point of time for which the path was passed.Remember, this ratio is simple.Traditionally, the distance represented by the letter s (from the Latin spatium - «Space"), speed - v (Eng. Velocity), and the time - t (Eng. Time).Draw a triangle, the top of which the distance, and at the bottom - the time and speed (see. Figure).Now close the desired value (eg, time).It turns out that time is the remaining fraction - ratio of the distance to the speed.
Closely supervise units quantities.If the problem is determined speed in meters per second, and the distance in kilometers, will either have to convert the speed in km / h, or the distance in meters.
- Physical Encyclopedic Dictionary