Which of the following best describes the difference between a vector quantity and a scalar quantity?

• A. A vector quantity has both $\mathrm{magnitude}$ and $\mathrm{direction}$, while a scalar quantity has only $\mathrm{magnitude}$.
• B. Both vector and scalar quantities have only $\mathrm{direction}$.
• C. A vector quantity has only $\mathrm{magnitude}$, while a scalar quantity has both $\mathrm{magnitude}$ and $\mathrm{direction}$.
• D. Both vector and scalar quantities have only $\mathrm{magnitude}$.

Answer: (A)

Verified step by step guidance

1. Understand that physical quantities can be classified into two main types: scalar quantities and vector quantities.
2. Recall that a scalar quantity is described completely by its magnitude (a numerical value) alone, without any direction. Examples include temperature, mass, and time.
3. Recognize that a vector quantity requires both magnitude and direction to be fully described. Examples include displacement, velocity, and force.
4. Compare the definitions: a vector quantity has both magnitude and direction, whereas a scalar quantity has only magnitude.
5. Conclude that the best description distinguishing vectors from scalars is that vectors have both magnitude and direction, while scalars have only magnitude.