Question

A body goes from P to Q with a velocity of 40 ms -1 and comes back from Q to P with a velocity of 60 ms -1. What is the average velocity of the body during the journey? Pls do step by step solution........

Answer 1

Given :-

• A Body goes from P to Q with a velocity 40m/s

• Come back from Q to P with velocity 60m/s

To Find :-

• The average velocity of body during the journey !

★ Solution !

In the journey the distance of body remains same .

$\bigstar{\boxed{\sf\ Average\ velocity = \dfrac{displacement }{Total \ time }}}$

• First we have to find the Time Using formula

$\sf \ speed = \dfrac{Distance}{Time }$

• Time for Going P to Q
• Let distance be z

$\sf \ speed_1 = \dfrac{Distance_1 }{Time_1}\\ \\ :\implies\sf 40= \dfrac{z}{t_1}\\ \\ :\implies\sf 40\times t_1= z\\ \\ :\implies\sf t_1= \dfrac{z}{40}$

Now time for coming back Q to P

Distance = -z

$\sf \ speed_2 = \dfrac{Distance_2}{Time_2}\\ \\ :\implies\sf 60= \dfrac{z}{t_2}\\ \\ :\implies\sf 60\times t_2= -z\\ \\ :\implies\sf t_2= \dfrac{-z}{60}$

Now find the Average velocity

The body returns back to his initial position , So it's average velocity will be 0

Distance Of P to Q = z

Distance of Q to P= -z

The average velocity

$:\implies\sf Average \ velocity = \dfrac{displacement (d_1+d_2)}{time (t_1+t_2) }\\ \\ :\implies\sf Av. \ velocity = \dfrac{-z+z}{\dfrac{z}{40}+\dfrac{-z}{60}}\\ \\ :\implies\sf Av. \ velocity = 0\times \dfrac{3z-2z}{120}\\ \\ :\implies \sf Av. \ velocity =0\times \dfrac{z}{120}\\ \\ :\implies\sf Av. \ velocity = 0 m/s$

$\underline{\textsf{\textbf{\dag\ Average \ velocity \ of \ body = 0m/s}}}$

• You can also find it without calculating time , because it's displacement becomes 0 and if we divide it by t ime

• Answer= 0 m/s

Answer 2

_______________________________

✰Question ✰

A body goes from P to Q with a velocity of 40 ms -1 and comes back from Q to P with a velocity of 60 ms -1. What is the average velocity of the body during the journey?

_______________________________

Given :-

• velocity of body goes P and Q =40m/s
• velocity of body return Q to P =60m/s

_______________________________

To Find :-

Average velocity of body.

_______________________________

Concept :-

☛We know that the displacement is the shortest path between two points.

☛ It is vector quantity.

☛ It SI unit is metre (m).

And ,

☛velocity is defined as the displacement per unit time.

☛It is vector quantity

☛It SI unit is m/s.

Average velocity =Total displacement /time taken

Solution :-

Let, the total time taken by body =t

here, the body starts from its initial position P and goes to final position Q and again return to it's initial position. then,

the Displacement of body is Zero.

∴Displacement =0

Now,

☛Average velocity =Displacement /Time taken

☛ Av. Velocity =0/t

☛ Av. velocity =0m/s

∴The Average velocity of body is 0m/s.