What happens when the brake pedal is depressed?

When the brake pedal is depressed, the correct outcome is that the brakes are applied. This process involves a series of mechanical and hydraulic actions designed to reduce the speed of the vehicle or bring it to a complete stop. The brake pedal is connected to the vehicle's braking system, and pressing it activates components like the master cylinder, which generates hydraulic pressure in the brake lines. This pressure engages the brake pads or shoes against the brake rotors or drums, creating friction that slows down the wheels.

Understanding this mechanism highlights the importance of the braking system's role in vehicle safety and control. The other choices relate to different functions that do not occur when the brake pedal is engaged. The vehicle accelerating or remaining stationary are outcomes that can occur due to other factors but are not direct results of pressing the brake pedal. Similarly, adjusting the steering is unrelated to the braking action and pertains to the manipulations of the driver's control over the vehicle's direction rather than its speed.