Which quantity has both magnitude and direction?

Which quantity has both magnitude and direction?

• A. Time
• B. Distance
• C. Velocity
• D. Speed

Answer: (C)

Some quantities have both a size and a direction—these are vectors. Velocity is the rate at which position changes, so it tells you how fast something is moving and in which direction. That combination gives it a magnitude (the speed) and a direction. Speed, by contrast, only tells you how fast and has no direction. Time measures duration, not motion in space, and distance is how much ground is covered, but neither includes a direction component. For example, a car moving 60 km/h to the north has a velocity of 60 km/h toward the north. So, the quantity that has both magnitude and direction is velocity.

Some quantities have both a size and a direction—these are vectors. Velocity is the rate at which position changes, so it tells you how fast something is moving and in which direction. That combination gives it a magnitude (the speed) and a direction. Speed, by contrast, only tells you how fast and has no direction. Time measures duration, not motion in space, and distance is how much ground is covered, but neither includes a direction component. For example, a car moving 60 km/h to the north has a velocity of 60 km/h toward the north. So, the quantity that has both magnitude and direction is velocity.