A quantity that has both magnitude and direction is called a

• A. Resultant
• B. Scalar
• C. Vector
• D. Undefined unit

Answer: (C)

A quantity that has both magnitude and direction is a vector. A vector is like an arrow: its length represents how much there is (magnitude) and the direction the arrow points shows which way it acts. Scalars, by contrast, have only magnitude and no direction—things like mass, temperature, and time. The term “resultant” refers to the outcome of combining vectors, which is itself a vector, but it’s specific to a summed effect rather than the general category. An undefined unit doesn’t describe a quantity with direction. So the label that fits any quantity with both size and direction is a vector.