Final answer:
Hydraulic cylinders can lift large loads by applying force to a smaller diameter cylinder, which is then transferred to a larger diameter cylinder, hence increasing the exerted force due to the area ratio between the cylinders.
Step-by-step explanation:
Some hydraulic cylinders can lift more than a large car; this is an application of principles in physics, specifically in the area of mechanics and fluid dynamics.
Hydraulic systems utilize Pascal's Principle, where an applied pressure on a confined fluid is transmitted undiminished in all directions throughout the fluid. By applying a force to a smaller diameter cylinder (master or pedal cylinder), which then gets transferred to a larger diameter cylinder (slave, wheel, or secondary cylinder), these systems can greatly increase the force exerted. This is analogous to how levers work, but with the advantage that hydraulic systems can transfer that force over distances and around corners.
For example, to support a 2000-kg car using a hydraulic lift system, a certain force must be applied to a primary cylinder. The force required depends on the diameters of the primary and secondary cylinders. We can apply formulas from physics to calculate the necessary input force, considering the car's weight and the area ratio between the two cylinders.
As more cylinders are added into a system, like wheel cylinders, each will exert a force and support part of the load, but they all move through a smaller distance compared to the pedal or master cylinder, due to the conservation of work. This principle states that a hydraulic system cannot do more work than the energy or work inputted into it.
In more advanced systems such as those in construction equipment or vehicles with power brakes, a motorized pump is often employed to do most of the work, providing the necessary force to move the larger loads. In nature, we can see hydraulics at play in the movement of a spider's legs, allowing some species to jump multiple times their body length.