Question

with the help of an example explain when do we say that object is at rest and when we say that it is moving

Answer 1

A body will be said in motion if it changes it position continuously with respect to the stationary object around it.
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Motion is a relative term. To know that whether a body is moving or not we have to relate the position of that body to the position of another body.
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To consider a thing as moving, we have to measure its distance from a stationary point at different time intervals.
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Everything in this universe is not stationary so everything in this universe are said to be in motion.