Final answer:
Air brakes on vehicles like trucks and trains use compressed air to operate, with this system being a substantial innovation by George Westinghouse in 1869. Compressed air is preferred for its efficiency and reliability. Pascal's principle plays a role in explaining how the pressure is distributed through the brake system to apply the brakes.
Step-by-step explanation:
Air brakes on vehicles, particularly on large trucks and trains, use compressed air to operate the braking system. These systems rely on a supply of compressed air to exert pressure on the brake pads, bringing the vehicle to a stop. The innovation of air brakes was a significant advancement in rail transport; they were invented by George Westinghouse in 1869. Before air brakes, the process of slowing down trains was much more hazardous and relied on manual labor.
Compressed air is chosen over options like compressed gas or oil because it is more efficient and less compressible under these circumstances, ensuring quicker and more reliable braking response times. This concept leverages physical principles, such as Pascal's principle, which explains how pressure applied to a confined fluid is distributed undiminished through the fluid.