Which of the following is not a vector quantity?

• A. $\mathrm{Velocity}$
• B. $\mathrm{Displacement}$
• C. $\mathrm{Acceleration}$
• D. $\mathrm{Speed}$

Answer: (D)

Verified step by step guidance

1. Understand the difference between scalar and vector quantities. Scalars have only magnitude, while vectors have both magnitude and direction.
2. Identify the quantities given: Velocity, Displacement, Acceleration, and Speed.
3. Recall that Velocity is a vector because it includes both speed and direction.
4. Displacement is a vector as it represents the change in position with direction.
5. Acceleration is a vector since it describes the rate of change of velocity, which includes direction, whereas Speed is a scalar because it only has magnitude without direction.