Lesson 7: Position, Distance and Displacement
Video Lesson
simulation (Distance and displacement)
Lesson Objective
Dear Learners,
At the end of this section, you should be able to:
- Define motion, position, and displacement;
- Describe motion in terms of frame of reference;
- Differentiate between position, distance and displacement;
- Draw diagrams to locate objects with respect to a reference frame.
Brainstorming Question
What is the distance around a standard football field? Is distance a positive or negative quantity?
Key terms and concepts
- Position
- Displacement
- Distance
Position describes a specific location in a reference frame.
Displacement measures how far and in what direction an object has moved from its initial position, making it a vector quantity.
Distance measures the total path length travelled by an object without regard to direction, making it a scalar quantity.
Position
Definition: Position refers to the location of an object in a particular frame of reference, often described by coordinates.
Example:
- If a point on a graph is at coordinates (3, 4), its position is defined relative to the origin (0, 0).
Distance
Definition: Distance is a scalar quantity that measures the total length of the path travelled by an object, regardless of direction.
Key Characteristics:
- It is always positive and does not consider the direction of movement.
- It is the actual path length covered.
Example:
- If an object moves 3 meters north and then 4 meters east, the total distance travelled is 7 meters.
Displacement
Definition: Displacement is the vector quantity that denotes the change in position of an object. It has both magnitude and direction.
Key Characteristics:
- Formula: S = X f – Xi ;The change in the student’s position, Xf – Xi ,is called a displacement.
- Where X f is the final position vector and Xi is the initial position vector.
Example:
- If an object moves from position (1, 2) to (4, 6), the displacement is the vector from (1, 2) to (4, 6).
- It is the shortest straight-line distance between the initial and final positions.
- It considers the direction of movement.
Here is the figure below that shows the difference between distance and displacement of the motion covered from point to point.
