Activity 8.1 Class 9 Science Chapter 8 Motion
Answer:
An object is in motion or not depends on the object and the observer both. Generally, whenever someone asks about the motion of the object it also says the observer position. The position of observer plays an important part in confirming whether an object is in motion or not. For example, a person sitting on a movable bus will look moving to a person sitting at the bus stop. However, if the observer also comes inside the bus, he will see the person as still.
(When the question does not tell the position of the observer we assume nearby objects.)
Celestial perspective
The universe itself is in motion since big-bang. All bodies are moving away from each other. Irrespective of its planets are also evolving around its sun. If we change the frame of reference to celestial bodies; one may say that since earth is moving, the wall is also moving along with it.
Fact: We use the term Relative motion for such things.
See also:
Activity 8.2 Class 9 Science Chapter 8 Motion.
Activity 8.3 Class 9 Science Chapter 8 Motion.
***Activity 8.1 Class 9 Science Chapter 8 Motion***
Ref: Book chapter eight.
