Final answer:
Hydraulic systems use liquids such as mineral oil-based fluids, water-based fluids, synthetic fluids, and biodegradable fluids. These liquids help transmit pressure based on Pascal's Principle, enabling controlled operation of machinery and lift systems like hydraulic jacks.
Step-by-step explanation:
Four types of liquids commonly used in hydraulic systems include mineral oil-based fluids, water-based fluids, synthetic fluids, and biodegradable fluids. Mineral oil-based fluids are widely used due to their lubricating properties and stability. Water-based fluids, which include water-glycol solutions and water-oil emulsions, are used for their fire-resistant properties. Synthetic fluids, such as phosphate esters, are selected for high-temperature applications and biodegradable fluids are used in environmentally sensitive areas because they break down more easily than other hydraulic fluids.
Hydraulic systems rely on Pascal's Principle to operate, where pressure exerted on a fluid is transmitted uniformly throughout the fluid, allowing for controlled movement and lifting in machinery such as automotive brakes, hydraulic jacks, and heavy equipment like backhoes. A hydraulic jack is an example of a hydraulic system that employs such a principle to lift heavy loads with a small force applied over a small area on one side of a U-tube balanced against a larger force over a larger area on the other side.