What unit is commonly used to express velocity?

Velocity is commonly expressed in meters per second (m/s) because it denotes the distance traveled in meters within a given time frame of one second. This unit is standard in physics and engineering and provides a clear, quantifiable measure of how fast an object is moving in a specific direction.

In contrast, the other units listed serve different purposes: Newtons (N) measure force, pounds (lb) measure weight, and liters (L) measure volume. Each of these units is crucial in its respective area but does not pertain to the measurement of velocity. Therefore, the meter per second remains the correct and standard unit for indicating velocity in a scientific context.