Position, Path Length, and Displacement

Words like “position,” “path length,” and “displacement” are frequently used when describing the location, trajectory, and distance traveled of moving objects. Despite their  simplicity, these ideas are essential to understand motion in physics and aid in our comprehension of how objects move. To better understand what they stand for and how they differ, let’s examine each one in more detail.

1.Position: Defining the Location of an Object

Placement of an object in space at any given moment is called its position. Consider a system of coordinates, such as a map grid, in which each point has a different coordinate (for example, x and y on a two-dimensional plane). Position provides the precise location of an object on that grid.
A quantity with both magnitude (size or value) and direction is usually used to indicate the position. Position of an automobile  is defined as a vector pointing east with a magnitude of 5 kilometers if it is situated 5 kilometers east of a reference point from your home. Position vectors make easy the understand about object’s location as well as its direction relative to a reference point.
Position, Path Length, and Displacement-Athletes path grid
Athletes path grid

2. Path Length: The Total Distance Traveled

The term “path length” describes the actual distance traveled by an object, independent of direction, as it travels from one location to another. It is the entire distance traveled by an object as it moves, measured along the path.
The overall distance you travel indicates the length of the path, even if it winds through several streets. Path length is a scalar quantity in this sense; it has simply magnitude and no direction. Path length is simply the sum of all the lengths you travel, regardless of whether you walk straight forward or take multiple detours.
For calculating the distance, an object has traveled over time, path length is frequently utilised. A cyclist on a curving track, for will estimate the total amount of ground covered because the path length equals the sum of the little distances traveled along the curves.
Position, Path Length, and Displacement-cyclist on path
Cyclist on path

3. Displacement: The Shortest Distance from Start to Finish

Displacement is the smallest straight-line distance between the starting and finishing points of an object’s route. Displacement of an objects is the change in the position of an object in a fixed direction. As displacement has both magnitude and direction, so it is a vector quantity.  
Suppose we start from point A, travel around for a while, and then arrive at place B. Displacement only considers the direct distance between points A and B, regardless of the overall distance you traveled (path length). This means that our displacement would be a straight line from our starting point to our destination, even if we choose a lengthy path.
Displacement’s direction is vital. For example, our displacement is not 7 kilometers if you walk 3 kilometers north and then 4 kilometers east, it is the distance, calculated using the Pythagorean theorem, that would be 5 kilometers northeast if we were to walk a straight line between the start and finish points.

Differences Between Path Length and Displacement

Path Length

Displacement

This is scalar quantity and has magnitude only,  indicates how much length the object has covered overall. It only considers the total distance, not the direction.
This is vector quantity, which measures the straight-line distance between start and finish points, has both magnitude and direction. It is actual path taken, it concentrates on the most shortest distance between two points.
  • Example :- A 400-meter track and an athlete completing a full lap. The path is 400 meters long. But since the runner returns to the starting spot, there is no displacement.

Practical Applications

Position, path length, and displacement are fundamental ideas in many disciplines, including engineering, physics, navigation, and even sports. Knowing them can help GPS systems plot directions, engineers create more efficient routes, and athletes gauge their performance by comparing direct displacement to actual distance traveled.
Position, Path Length, and Displacement-GPS systems
GPS systems
Note :-
The ideas of position, path length, and displacement give us an organised understanding of motion. Even though they might appear simple, how they differ is essential to understand more difficult physics and navigational concepts. Path length indicates the total amount of ground traversed, position indicates the location of an object, and displacement gives the direct path between two places.
An object’s position is its precise placement in space at a given point in time. In physics, it is frequently expressed in terms of coordinates, such as (x, y), in a two-dimensional plane and is depicted as a vector from a reference point, like the origin.
A route length is a scalar quantity that is defined as the entire distance traveled by an object along its real route, independent of direction. The smallest straight-line distance, including direction, between an object’s starting and finishing positions is represented by displacement, a vector quantity.
When an object travels from its beginning point to its endpoint in a single direction in a straight line, the route length and displacement are equal. The shortest distance between the two points (displacement) and the total distance traveled (path length) match.
Yes, displacement can be zero if an object returns to its starting position, making the net change in position zero. if we walk in a circle and end up where you started, our path length is the total distance we walked, but our displacement is zero.
Because it has both direction and magnitude, displacement is regarded as a vector quantity. To determine how far and which way the object has moved in relation to its starting position, this directional information is vital.
When we want to know how far an object has gone overall, regardless of direction, we utilise path length. This is frequently useful for measuring performance in sports involving constant movement or for determining the amount of energy or time used, such as in trekking, when the precise path traveled counts
To calculate displacement when an object moves along a curved path, we measure the straight-line distance from the starting point to the ending point, using vector addition if needed. We can ignore the curves in the path since displacement only considers the initial and final positions in a direct line

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