Question

A body moving along straight line covers a distance
in three equal parts with speed 2 m/s, 3 m/s and
4 m/s, then its average speed is​

Answer 1

Explanation:

let the total distance be 3x

the time required are x/2,x/3,x/4respectively

Avg speed =total distance /total time

=3x/x/2+x/3+x/4

=3x/13x/12

=36/13m/s

Answer 2

Given :

A body moving along straight line covers a distance  in three equal parts with speed 2 m/s, 3 m/s and  4 m/s

To Find :

Average speed of the body

Solution :

Average Speed : It is defined as total distance covered per total time

$:\implies \sf Average_{Speed}=\dfrac{Total_{Distance}}{Total_{Time}}$

        x        x        x

   |-------|-------|-------|

     2 m/s  3 m/s 4 m/s

Total distance covered = x + x + x

➠ Total distance = 3x m

Speed for 1st third distance = 2 m/s

Distance for 1st third distance = x

Time for 1st third distance = x/2 s

Like wise ,

Time for 2nd third distance = x/3 s

Time for 3rd third distance = x/4 s

Total time is ,

➠ $\sf \dfrac{x}{2}+\dfrac{x}{3}+\dfrac{x}{4}$

➠ $\sf \dfrac{6x+4x+3x}{12}$

➠ $\sf \dfrac{13x}{12}\ s\ \; \orange{\bigstar}$

Now Average speed is ,

$:\implies \sf \dfrac{Total_{Distance}}{Total_{Time}}$

$:\implies \sf \dfrac{3x}{\frac{13x}{12}}$

$:\implies \sf \dfrac{\textsf{\textbf{36}}}{\textsf{\textbf{13}}}\ \textsf{\textbf{m/s}}\ \; \green{\bigstar}$