Rectilinear Motion - Displacement

• Displacement measures how far and in which direction an object moves.
• It is the change in the object’s position between two times.
• Displacement is a vector quantity, so it has both magnitude and direction.
• Its unit is the metre (m).
• Direction is given by the line along which the object moves.

If the position at time t₁ is x₁ and at time t₂ is x₂, then
Displacement \[\vec s\] = \[\vec x_2\] - \[\vec x_1\]

• Displacement depends only on initial and final positions.
• It does not depend on the path taken between the two points.
• It has the same dimensions as length ([L]).
• It is positive, negative, or zero depending on direction.
• Its direction is along the line of motion.

• Walking 5 m east from home and stopping: displacement = 5 m east.
• Swimming straight 20 m toward the shore: displacement = 20 m toward shore.
• Driving from school to home, 3 km south: displacement = 3 km south.
• A bird flying 10 m up from a tree branch: displacement = 10 m upward.