Write a short note on hydraulic brakes.

(N/A) Hydraulic brakes operate on the principle of Pascal's law.
When a driver applies a force $F_1$ on the brake pedal,the master piston,which has a small cross-sectional area $A_1$,moves into the master cylinder. This action pushes the brake oil through the tubes into the wheel cylinder.
The wheel cylinder contains two pistons with a much larger cross-sectional area $A_2$. According to Pascal's law,the pressure applied is transmitted equally throughout the fluid. Since $A_2 \gg A_1$,a much larger force $F_2$ is exerted on the wheel pistons,where $F_2 = F_1 \times (A_2 / A_1)$.
This large force $F_2$ pushes the brake shoes outward,bringing them into contact with the rotating wheel rim,thereby applying the brakes.
When the driver releases the brake pedal,a restoring spring pulls the brake shoes back to their original position,releasing the wheel rim. The brake oil flows back into the master cylinder as the pistons return to their initial positions.