In the context of vectors and scalars, what is the key difference between speed and velocity?

• A. Speed and velocity are both vectors because they can be negative.
• B. Speed is a scalar (magnitude only), while velocity is a vector (magnitude and direction).
• C. Speed includes direction, while velocity is only the magnitude of motion.
• D. Speed is the rate of change of displacement, while velocity is the rate of change of distance.

Answer: (B)

Verified step by step guidance

1. Understand the definitions: Speed is a scalar quantity, which means it only has magnitude (how fast an object is moving) without any direction.
2. Velocity, on the other hand, is a vector quantity, meaning it has both magnitude and direction (how fast and in which direction the object is moving).
3. Recognize that because velocity includes direction, it can be positive, negative, or zero depending on the direction of motion relative to a chosen reference.
4. Speed is always positive or zero since it does not consider direction, only the magnitude of motion.
5. Summarize the key difference: Speed measures how fast an object moves regardless of direction, while velocity specifies both how fast and in what direction the object moves.