Final answer:
The principles of traffic control devices relate to physics by illustrating how forces act on a system through a free-body diagram, balancing vertical and horizontal forces to keep a traffic light suspended.
Step-by-step explanation:
The principles of traffic control devices can be directly correlated with principles of physics, specifically when discussing the forces involved in suspended objects such as traffic lights. A free-body diagram is a crucial tool used to visualize and solve problems related to forces acting on a system.
For a traffic light suspended by two wires, we can demonstrate how the forces acting on the traffic light can be decomposed into vertical and horizontal components. The horizontal components of the tension in the wires must cancel each other out for the system to be in equilibrium, meaning they must be equal in magnitude but opposite in direction.
Simultaneously, the sum of the vertical components of the tensions must equal the weight of the traffic light, ensuring it remains stationary in the air. The principles observed here are also applicable to traffic control safety measures, where the installation of traffic signals is influenced by the need to regulate vehicle speed and ensure pedestrian safety.