When is a body said to be in motion ?

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Motion**: A body is said to be in motion when it changes its position over time. This means that if you observe the body from a particular point, you will notice that its location is not constant.

2. **Reference Point**: To determine if a body is in motion, we need a reference point or an observer's frame of reference. This could be a stationary object or a specific location in space.

3. **Continuous Change**: The change in position must be continuous. This means that the body should not just move once and stop; rather, it should keep changing its position relative to the reference point.

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