Key Concept: Hydraulics as Force Multipliers
Hydraulics may sound complicated, but they’re essentially force multipliers. They work because:
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Liquids are virtually incompressible.
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When you apply pressure to a liquid, it is transmitted equally in all directions.
Analogy:
Think of a balloon with holes. Squeeze the top, and water squirts out of all holes — showing how the pressure is shared throughout the liquid.
Important Formula
Pressure (P)=Force (F)Cross-sectional Area (A)\text{Pressure (P)} = \frac{\text{Force (F)}}{\text{Cross-sectional Area (A)}}Pressure (P)=Cross-sectional Area (A)Force (F)
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Pressure → measured in Pascals (Pa)
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Force → measured in Newtons (N)
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Area → measured in square metres (m²)
Hydraulic System Example
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Input piston area: 0.001 m²
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Force applied: 15 N
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Pressure generated:
P=150.001=15,000 PaP = \frac{15}{0.001} = 15{,}000 \text{ Pa}P=0.00115=15,000 Pa
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Output piston area: 0.01 m²
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Force output:
F=P×A=15,000×0.01=150 NF = P \times A = 15{,}000 \times 0.01 = 150 \text{ N}F=P×A=15,000×0.01=150 N
So, a small force on a small piston creates a larger force on a larger piston — this is how hydraulic multipliers work!
Real-Life Applications
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Car braking systems
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Car jacks
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Aircraft landing gear
These systems allow small effort forces to generate large output forces, making heavy tasks easier — like changing a tyre!
References:
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BBC Bitesize – GCSE Physics
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CGP GCSE Physics AQA Revision Guide
