Physics, asked by EshaxYuta9173, 11 months ago

Why do we say that rest and motion are relative terms?

Answers

Answered by atul34567
7
Rest and motion are relative because they depend on the observe 's frame of reference....so if they two different observes are not at rest with respect to each other ,then they too get different result when they observe the rest or motion of the body
Answered by GovindRavi
3
First you should understand the term
=> Rest
=> Motion

Rest
====
Nothing is at rest here...' Everthing is in Motion '...
If you are in ur room and look at your any of the Wall...you may say...Wall is at rest...
But if someone watch the same Wall from the space, it will keep changing its position with respect to time...
As our Earth is rotating on its own axis and it also revolve around the Sun...
So in our Earth , nothing is at rest...
If you say person , Looking from the planet will definetly at rest , No it will not...because planet also revolve around the Sun...
Even Our Sun is not at rest...it is moving...So Universe is expanding....So nothing is at rest...

If nothing is at rest , then how can we define the term rest...
To define rest...we have to be in a particular frame or surrounding...By considering that surrounding, we can simply define the term rest...

An object is said to be at rest if it doesnt change its podition with respect to time or observer or surroundings...
Example : - Suppose you are in classroom , and look at your blackboard...You will find that board is at rest with respect to you ( Observer ) or surrounding ( Classroom ) or You can observe that as time keeps on changing but the position of board is not changing at all...

This is how we difine a term rest...

Motion
======
An object is said to be in motion if its position is changing with respect to time ( Observer or Surroundings )...
Example : - look at the Tips of a Wall clock , you will observe that everytime its position is changing as the time changes...So we say tips of the clock are in motion...Similary you can think of many situations around you...

Now lets Answer your Question
============================
Suppose two persons A and B are sitting in moving bus with some velocity.
If person A observe the Person B , he will observe that B is at rest ( as time changes but position of person B doesnt changes )...But if the another person C sitting in the park and observe the person B who is sitting the moving bus will say Person B is in motion as its position is changing with rest to observer C...

( So think Can we say here whether a person B is at rest or in motion...If A say B is at rest...is it true for all observer that B will definetly at rest Or if C say B is in motion then B will be in motion for all observer...No it isnt...This means rest and motion are not absolute terms...)

Here we say Person B is at rest in relation (respect) with Person A whereas Person B is in motion in relation with person C...So We have to specify the observer here with these terms => Rest and Motion....
So rest and motion are relative terms not an absolute....




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