In the context of vectors and scalars, the main difference between speed and velocity involves which quantity?

• A. Time interval (speed requires time, velocity does not)
• B. Units of measurement (speed is in m/s, velocity is in m/s²)
• C. Direction of motion (velocity includes direction; speed does not)
• D. Distance traveled (velocity uses distance, speed uses displacement)

Answer: (C)

Verified step by step guidance

1. Understand the definitions of speed and velocity: Speed is a scalar quantity that measures how fast an object is moving, while velocity is a vector quantity that measures both how fast and in which direction the object is moving.
2. Recall that scalar quantities have only magnitude (size), whereas vector quantities have both magnitude and direction.
3. Recognize that speed is calculated as the total distance traveled divided by the time interval, and it does not include any information about direction.
4. Recognize that velocity is calculated as the displacement (change in position) divided by the time interval, and it inherently includes the direction of motion.
5. Conclude that the main difference between speed and velocity is that velocity includes direction, making it a vector, while speed does not include direction, making it a scalar.