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

Answer:

A body moving in a straight line covers distance of:

A B C

-+------------------------+------------------------+

2m/s 3m/s 4m/s

then average speed is:....

(Average speed)=v.

v. = total distance /total time

time: tA = (s/3)/2 = s/6

tB = (s/3)/3 = s/9

tC = (s/3)/4 = s/12

v.= (S/3)+(S/3)+(S/3)

------------------------------

(S/6)+(S/9)+(S/12)

= S

---------------------------

(S/6)+(S/9)+(S/12)

= S

-------------------------

(6s + 4s + 3s)

--------------------

36

= 36 s 36

-------------------- = ----------

13s 13

= 2.76 kmph

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 ,

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

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

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