Question

Describe briefly with the help of a diagram, a hydraulic lift used in service stations.

Answer 1

1. Hydraulic lift, also known as hydraulic jack works on the principle of Pascal's law.
2. Pascal's Law states that 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.
3. A hydraulic lift is used for lifting heavy vehicles such as cars, trucks, etc. in service stations for their repair.
4. The fluid is enclosed in the tube by two leak-proof pistons in each arm as shown in the figure,

The ratio of cross-section areas of the right and tube tubes is,

$A_2:A_{1}and{A}_2>A_1$.

1. When a force $F_1$ is applied to the left piston, the excess pressure acting on the fluid volume is $\frac{F_1}{A_1}$.
2. According to Pascal's principle, this excess pressure is transmitted equally throughout the fluid volume.
3. So, every unit area of the fluid experiences pressure of $\frac{F_1}{A_1}$.
4. The excess pressure in the right side tube is also $\frac{F_1}{A_1}$.
5. The pressure in the right side tube can also be written as $\frac{F_2}{A_2}$.
6. Equating both, we get,

$$\begin{gathered} \frac{F_2}{A_2}=\frac{F_1}{A_1} \\ \Rightarrow F_2=F_1\times \frac{A_2}{A_1} \end{gathered}$$

Thus the application of Pascal's results in a large upward force on the right piston when a small downward force is applied to the left piston.