Final answer:
The minimum height of a horizontal guard depends on regulations such as building codes and safety standards.
Step-by-step explanation:
The minimum height of a horizontal guard depends on the context and regulations. In the field of physics, a horizontal guard could refer to a safety railing or barrier used to prevent falls or accidents.
In this case, the minimum height is often determined by building codes and safety regulations, which vary depending on the location.
For example, in the United States, the Occupational Safety and Health Administration (OSHA) requires that the top edge of a guardrail system be at least 42 inches above the working level. This ensures proper protection and safety for workers. However, specific regulations may differ in other countries or industries.
It's important to check local building codes and regulations to determine the minimum height required for a horizontal guard in a specific situation.