What happens when you push down on the brake pedal?

Answer: B — Air pressure is applied to the brake pads

When you push down on the brake pedal in a vehicle equipped with air brakes, air pressure is applied to the brake pads. This is the operation method of air brake systems, where pressing the brake pedal sends a signal through the system to activate the brakes. When the pedal is depressed, it opens a valve that allows compressed air from the air tanks to flow into the brake chambers. This air pressure pushes out the brake pistons, which in turn press against the brake pads or shoes, creating the necessary friction to slow down or stop the vehicle. Understanding this mechanism is crucial for safe driving, especially for large vehicles that utilize air brakes, as it affects both the stopping power and the overall control of the vehicle. Other options may pertain to different aspects of the braking system but do not directly describe the immediate outcome of pressing the brake pedal in the context of air brakes.