Let's analyze the given statements regarding motion and rest. These are fundamental concepts in physics that describe how objects change their position.

Analyzing Statement 1: Defining Motion

The first statement says: If a body changes its position with time it is said to be moving.

• Motion is defined as the change in the position of an object over time relative to a reference point.
• If an object's location is different at one moment compared to a previous moment, assuming a fixed viewpoint (reference point), then the object is in motion.
• For example, a car driving down a road changes its position relative to the road markers over time.

This statement perfectly aligns with the scientific definition of motion. Therefore, Statement 1 is true.

Analyzing Statement 2: Relative Nature of Rest and Motion

The second statement says: Nothing is in absolute rest or in absolute motion.

• In physics, rest and motion are generally considered relative concepts. This means that whether an object is at rest or in motion depends on the frame of reference from which it is observed.
• A frame of reference is a coordinate system or a point of view from which observations are made.
• Consider a person sitting inside a moving train. Relative to other passengers or the train carriage, the person is at rest (not changing position). However, relative to someone standing on the ground outside the train, the person is in motion (changing position as the train moves).
• There is no universally fixed point or frame of reference in the universe that we can definitively say is in "absolute rest". Even seemingly stationary objects on Earth are moving as the Earth rotates on its axis, orbits the Sun, and the Sun moves within the galaxy.
• Therefore, rest and motion are always described relative to something else. There is no concept of absolute rest or absolute motion independent of any reference frame in classical physics.

This statement accurately describes the relative nature of rest and motion. Therefore, Statement 2 is true.

Conclusion on True Statements

Based on the analysis:

• Statement 1 is true because motion is defined by a change in position over time relative to a reference.
• Statement 2 is true because rest and motion are relative concepts, dependent on the frame of reference, and there is no known absolute frame of rest or motion.

Since both statements are true, the correct option is the one that states "Both 1 and 2".

Additional Information: Extending Concepts

Understanding motion and rest often involves other related concepts:

• Reference Frame: A system used to describe the location and movement of an object. It consists of an origin and a set of axes.
• Distance: The total path length covered by a moving object. It is a scalar quantity.
• Displacement: The shortest straight-line distance between the initial and final positions of an object. It is a vector quantity.
• Speed: The rate at which an object covers distance. Speed \( = \frac{\text{Distance}}{\text{Time}} \).
• Velocity: The rate of change of displacement. Velocity \( = \frac{\text{Displacement}}{\text{Time}} \). It is a vector quantity, including both magnitude and direction.

These concepts help us quantify and further analyze the motion of objects.