ASVAB (Armed Services Vocational Aptitude Battery)Mechanical Comprehension (MC)Medium
A driver presses the brake pedal, which uses a hydraulic system to slow the car. What fundamental principle of fluid mechanics explains how a small force on the pedal can generate a much larger force at the brake calipers?
- AArchimedes' Principle
- BBernoulli's Principle
- CNewton's Third Law
- DPascal's Principle
Show answer & explanationAnswer & explanation
Correct answer: D. Pascal's Principle
Pascal's Principle states that a change in pressure at any point in an enclosed incompressible fluid is transmitted undiminished to all portions of the fluid and to the walls of its container. This allows a small force applied over a small area (brake pedal) to create a large force over a large area (brake calipers) due to equal pressure.
Why the other options are wrong
- A. Archimedes' Principle describes buoyancy, the upward force on an immersed object.
- B. Bernoulli's Principle relates fluid speed and pressure, often used for lift in aerodynamics.
- C. Newton's Third Law states that for every action, there is an equal and opposite reaction, which is a general principle, but not specific to fluid force multiplication in hydraulics.
Hydraulic Systems
Systems that use an incompressible fluid to transmit forces from one point to another, often to multiply force or change direction.
- Based on Pascal's Principle.
- Fluid is typically oil.
- Used in brakes, lifts, and heavy machinery.
Memory trick: Fluids Follow Fantastic Fundamental Facts!