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

3 m/s

Explanation:

Total distance travelled

2+3+4 m/s

9 m/s

Total time 1+1+1

3 second

$avg \: spped \: = \: total \: distance \div total \: time \\ 9 \div 3 \\ 3m s$

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 ,

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

➠ $\sf \dfrac{6x+4x+3x}{12}$

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

Now Average speed is ,

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

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

$:\implies \sf \dfrac{36x}{13}\ s\ \; \green{\bigstar}$