Tip 1: How to find the average speed

Central speed can calculate by dividing the length of the path traveled by the body in the time spent on it.But in practice when solving physical problems, it is important to remember and some special nuances.
Calculate the average speed body moving uniformly throughout the stretch of track.This speed calculated easiest as it does not change on the whole interval movement and equal to the average rate.You can write this as a formula: = Vrd Vav where Vrd - speed uniform motion , and Vav - average speed .
Calculate the average speed ravnozamedlennogo (uniformly accelerated) movement at the site, which must be added to the start and end speed .Halve the result, which will be the average speed th.You can write it more clearly as a formula: Vav = (Vr + Vc) / 2, where Vr is the initial speed , and VR - end.
use a special variant of the above formula, if we know the magnitude of the acceleration and the initial speed , but not given a finite speed .Designate the acceleration factor as "a" and get the formula: VR = a * t + VH.Hence: Vav = (Vc + Vr) / 2 = (a * t + Vr + Vr) / 2 = a * t / 2 + Vr.
Convert the above formula, if the unknown initial speed , but given the acceleration and final speed : Vav = (Vr + Vc) / 2 = (VR + VR - a * t) /2 = VR - a * t / 2.
Calculate the average speed , if given the length of the distance traveled (S) and spent his passing time (t), dividing them.To do this, use the classic formula: Vav = S / t.Remember that you need to take full account of the time, even if the object is stopped during the passage area.

Tip 2: How to find the average speed

average speed - value which characterizes the object distance traveled in a given period of time (hour, rarely minute, second) on different parts of his movements.Calculation of the average speed is based on the distance and time of the object in motion.
How to find the average speed
you need
  • is the initial velocity of the object;
  • a finite speed of the object;
  • -Acceleration object all the way.
method 1. The calculation of the average speed over the starting and ending velocity of the body (at zero initial velocity):
U = (0 + u / 2) = u / 2, where
u- ultimate speed body.If the initial
speed is not zero, then:
U = (v + u) / 2, where
v - the speed of the initial body.
Method 2: Calculation of average speed through the acceleration of the object all the way:
U = at / 2, where
a - acceleration of the object of the time t.
If the problem is not specified, then the value is the desired average ground speed.Under passed by its calculation understand exactly the length of the trajectory along which the body moves.If during the movement the body returns again passed points, then these areas should also be considered and added to the total distance.