What is a practical example of a uniformly distributed load?

A uniformly distributed load refers to a load that is spread evenly across a structure, affecting its responses in a predictable manner. In this context, the correct choice illustrating a uniformly distributed load is related to the wind blowing on a tall building.

Wind affects the building's surface area uniformly, exerting pressure that is distributed across the entire height and width of the structure. This consistent force can be modeled as a uniform load for structural analysis since it acts in a similar manner across various points on the building, leading engineers to calculate the effects on stability and strength uniformly.

In contrast, a person standing in the middle of a beam represents a point load as it is concentrated at a single point, creating a localized stress rather than spreading it out. A car parked on a bridge can also be considered a point load in practical situations, particularly if it is by itself and not affecting a vast area. Similarly, a single heavy weight placed on one end of a beam creates a point load that results in bending and localized stress, rather than a distributed effect across multiple segments of the beam.