OxScience

Trajectory

For kinematics, the trajectory of a body is the locus of the positions through which it passes as it moves. It depends on a reference system in which said the movement is described, that is, the observer’s point of view.

For classical mechanics, the trajectory of a body is always a continuous line, while for quantum mechanics there are situations that are not like that. For example, the position of an electron in the orbital of an atom is probabilistic.

Displacement

The displacement is the vector that defines the position of a point or particle in relation to a point of origin with respect to a position. The vector extends from a reference point to the end position. Only the start position and the end position matter when moving, and their path is irrelevant.

For dynamics, the displacement is the vector or straight segment that joins the initial position with another generic point of the trajectory. This vector fully describes the motion and path of a particle during its path.

suggested video: Trajectory vs Displacement 

Differences between Trajectory and Displacement

• Displacement is a vector that indicates distance and direction traveled by an object.
• The trajectory is a locus that indicates the positions of a particle or object during its movement.
• The offset has a reference point that can be found at the initial position of the object.
• The trajectory has a reference point located at the observer’s position.