Which of the following describes a live load?

The correct understanding of a live load is indeed best captured by the notion of a load that can move, including people and furniture. Live loads are dynamic in nature and can change over time due to factors such as occupancy or the temporary placement of movable objects. This encompasses any weight that is not permanently attached to a structure and can vary, like the presence of people in the building, movable furniture, and other temporary items.

In the context of structural engineering and building design, live loads are essential to consider because they affect the stability and safety of a structure under changing conditions. They differ significantly from dead loads, which represent the static weight of all permanent components.

The other definitions do not accurately represent the concept of a live load. Permanent fixtures and the static weight of structural components relate to dead loads, which do not change over time. A constant, unchanging load also does not align with the characteristics of a live load, as it fails to recognize the variability inherent in such loads. Thus, the definition recognizing movement and variability is the most fitting for live loads.