(N/A) Pascal's Law: "$A$ change in pressure applied to an enclosed fluid is transmitted undiminished to every point of the fluid and the walls of the containing vessel."
$A$ hydraulic lift is based on this principle.
As shown in the figure, consider two cylinders with cross-sectional areas $A_{1}$ and $A_{2}$, where $A_{1} < < A_{2}$.
$A$ liquid is filled in this vessel.
$A$ piston of small cross-section $A_{1}$ is used to exert a force $F_{1}$ directly on the liquid. The pressure $P_{1} = \frac{F_{1}}{A_{1}}$ is transmitted throughout the liquid to the large cylinder attached with a larger piston of area $A_{2}$.
According to Pascal's law, the pressure is transmitted undiminished, so $P_{1} = P_{2}$.
Therefore, $\frac{F_{1}}{A_{1}} = \frac{F_{2}}{A_{2}}$, which implies $F_{2} = F_{1} \left( \frac{A_{2}}{A_{1}} \right)$.
Since $A_{2} > > A_{1}$, the force $F_{2}$ exerted on the large piston is much larger than the applied force $F_{1}$, allowing the lift to support heavy loads like a car.