Final answer:
In a hydraulic brake system, Pascal's Principle is used to transmit the force from the driver's pedal push throughout the brake fluid undiminished, leading to synchronized force output at the wheel cylinders.
Step-by-step explanation:
The key principle at work in a hydraulic system such as those found in modern vehicle's brake systems is based on Pascal's Principle. This principle states that when pressure is applied to an enclosed fluid, it is transmitted undiminished throughout the fluid, exerting an equal pressure at all points. In the context of hydraulic brakes, when a driver presses the brake pedal, a force is applied to the master cylinder, which contains brake fluid. This force is then transmitted through the hydraulic line to the brake cylinders at each wheel. Because the brake system is closed and the fluid is incompressible, the pressure is uniform and causes each wheel cylinder to exert the same force, achieving synchronized braking.
In more detailed terms, when a driver exerts a force on the brake pedal, a lever mechanism amplifies this force before it is applied to the brake fluid. This amplified force pushes the fluid into the wheel cylinders. If the cross-sectional areas of the master and wheel cylinders are represented by A1 and A2 respectively, and the force applied to the brake pedal is represented by F1, Pascal's Principle ensures that the force output F2 on the wheel cylinders is greater if the area A2 is larger than A1. This is how a smaller force exerted by the driver can generate a much larger force at the wheel cylinders, allowing for effective braking.