Pascal · Upthrust · Archimedes
Fluid pressure, hydraulic machines, buoyancy, floatation & relative density — with diagrams & interactive Q&A
Pascal’s Law & Applications
Pascal’s Law: Pressure applied to an enclosed fluid is transmitted undiminished to every portion of the fluid and to the walls of the container.
Formula: P = F/A → F₁/A₁ = F₂/A₂
📌 Hydraulic lift / brake: F₂ = F₁ × (A₂/A₁)
Applications
- Hydraulic jacks & presses
- Hydraulic brakes in vehicles
- Hydraulic power steering
- Water pressure systems
🔧 Diagram: Hydraulic lift – small force F₁ produces large F₂
Upthrust (Buoyancy) & Archimedes Principle
Upthrust (Buoyant force): When a body is immersed in a fluid, it experiences an upward force equal to the weight of the fluid displaced.
📖 Archimedes’ Principle: Apparent weight loss = weight of displaced fluid.
Fbuoyancy = ρfluid × Vsubmerged × g
Fbuoyancy = ρfluid × Vsubmerged × g
Real-world applications
- Ship floating (displaces water equal to its weight)
- Submarine: ballast tanks to control buoyancy
- Hot air balloons & hydrometers
- Lactometer & density measurement
📐 Submerged object: Buoyant force = ρfluid·Vdisp·g
Demonstration: Spring balance reading reduces when object is immersed in water → loss in weight = upthrust.
30 MCQs: Pascal, Upthrust & Archimedes
Click “Show Answer” after attempting
30 Numericals (Pressure, Buoyancy, Density)
Step‑by‑step hidden solutions
Quick Reference & Applications
Laws of Floatation
- Weight of floating body = weight of displaced fluid
- Density of body < density of fluid → floats partially
- Density of body = fluid density → neutral buoyancy
Relative density (R.D.) = ρ_substance / ρ_water = weight in air / loss of weight in water
Real life examples
- Iceberg: 90% volume submerged
- Hydrometer uses Archimedes to measure liquid density
- Balloons rise due to upthrust from air
- Swimming & floating easier in sea water (higher density)