Which of the following units can be used to measure both velocity and speed?

• A. $\frac{\mathrm{km}}{h}$ (kilometers per hour)
• B. $\mathrm{kg}$ (kilogram)
• C. $\frac{\mathrm{mi}}{h}$ (miles per hour)
• D. $\frac{m}{s}$ (meters per second)

Answer: (D)

Verified step by step guidance

1. Understand the difference between speed and velocity: Speed is a scalar quantity that measures how fast an object is moving, while velocity is a vector quantity that measures both the speed and direction of the object's motion.
2. Recognize that both speed and velocity are measured in units of distance divided by time, since they describe how much distance is covered over a certain period.
3. Identify the units given in the problem: kilometers per hour (km/h), kilograms (kg), miles per hour (mi/h), and meters per second (m/s).
4. Eliminate units that do not represent distance over time. For example, kilograms (kg) is a unit of mass, so it cannot measure speed or velocity.
5. Conclude that units like km/h, mi/h, and m/s are appropriate for measuring both speed and velocity because they represent distance divided by time.