# *Average speed

***Average speed**

Speed between two instants is called average. Mathematically it is measured as the total distance covered per unit time spent. It is scalar & always positive.

i.e. Average speed

- For a given time interval average velocity is single valued while average speed can have values depending upon path followed.
- Average velocity & average speed are equal only for motion along a straight line with no reversal.
- The average speed can never be – ve or zero while average velocity can be.
- If a particle travels distances x
_{1 }, x_{2 }& x_{3}with speeds v_{1 }, v_{2 }& v_{3 }during time intervals t_{1}, t_{2 }& t_{3 }respectively, then its average speed is If x_{1 }= x_{2 }= x_{3}, then this relation becomes harmonic mean of individual speeds. Also if t_{1}= t_{2}= t_{3}, then the average speed is be given by Arithmetic mean of individual speeds.