Lesson 1-Describing Motion: Position, Speed, and Velocity

Flashcards covering the concepts of position, reference points, distance and direction, positive/negative values, speed vs. velocity, and calculating average velocity.

What is position in describing motion?

An object's current distance and direction from a reference point.

What is a reference point in describing motion?

An object or place used to describe the locations of other objects; it serves as the 0 point for measuring position.

When using a reference point, what does the distance part describe?

The measurement from the reference point to the object (e.g., four car-lengths).

What does the 0 point on the number line represent in this context?

The reference point from which distances are measured.

How is direction described with respect to position?

By indicating whether the object is in front of or behind the reference point, or by using positive/negative direction values.

What does a positive position value indicate?

The object is in the positive (front/in front) direction from the reference point.

What does a negative position value indicate?

The object is in the negative (behind/behind) direction from the reference point.

What units are commonly used to describe distance in motion descriptions?

Meters (m) as a standard unit; car-lengths may be used informally in driving scenarios.

What is speed?

The rate at which an object moves, distance per unit time; speed does not include direction.

What is velocity?

An object's speed in a specific direction; velocity includes both magnitude (speed) and direction.

What is the formula for average velocity?

Average velocity = (end position − start position) ÷ time.

If an object moves from −70 m to 20 m in 3 s, what is its average velocity and direction?

Average velocity = (20 − (−70)) ÷ 3 = 90 ÷ 3 = 30 m/s; direction is east (positive).