An object is considered as a point object if the size of the object is much smaller than the distance it moves in a reasonable duration of time.

**Example:- **A train under a journey of several 100 KM can be considered as a point object.

## Position, Path Length and Displacement

### Position

It is define as the point where an object is situated. Position can be determined by the co-ordinate Axis that is marked in units of length and that has positive and negative directions.

If object at negative point it indicate negative direction, at zero indicate at rest and positive point indicate positive direction.

#### Frame Of Reference

We choose a rectangular coordinate system of three mutually perpendicular axis as X, Y and Z. The point of intersection of these three axis is called origin and considered as a reference point.

The X, Y, Z co-ordinate describe the position of the object with respect to the coordinates system. To measure time, we need a clock. This coordinates system along with a clock constitutes a frame of reference.

### Path Length / Distance

The length of the path covered by an object in a given time interval, is known as its Path length or distance travelled.

It’s SI unit is metre (m).

**Example:-** Let an object moves along x-axis to a distance of 100 m from the origin O in time t then, the path length is 100 m.

### Displacement

The change in position of an object in a particular direction is termed as displacement i.e the difference between the final and initial positions of the object is called displacement.

It is denoted by ∆x.

Displacement ∆x = x₂-x₁

Where, x₁ and x₂ are the initial and final position of the object.

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