Fluid-Mechanics GEN SCI

Pressure In Fluids

• Force applied over an area
  - exists in fluids ( liquids )

• Measured In pascals ( pa )

Pascal Principle

• Pressure applied to a confined fluid
  - transmitted equally in all directions
  - pressure remains undimished

hydraulic lift ( concept )

• in a hydraulic lift
  - small force is applieds to a small piston
  - pressure travels through the fluid
  - large piston lifts a heavy object

hydraulic lift diagram

• small piston
  - large piston
  - enclosed fluid

Yes

Applications of hydraulics

• garbage trucks
  - excavators
  - hydraulic lifts and presses

garbage trucks ( hydraulic system )

• use hydraulic piston to lift trash containers
  - small input force creates large lifting force
  - fluid pressure controls lifting and dumping motion

excavators ( hydraulics motion control )

• hydraulic cylinders move the arm the bucket
  - rotational and translational motion work together
  - small controls operate heavvy machinery

hydraulic lifts and presses ( industrial use )

• lift vvehicles or heavy loads
  - apply pressure evenly in enclosed fluids
  - used in workshops and industries

summary

hydraulic systems work because:
- pressure is trnasmitted equally
- small force becomes large force
-- based on pascals principle

review of simple machines

• lever
  - inclined plane
  - wedge
  - screw
  - wheel and axle
  - pulley

compounds machines

• combine simple machines
  - perform complex tasks efficiently
  
  examples
  - scissors
  - wheelbarrow
  - car jack

hydraulics in machines

• use fluid pressure
  - multiply force
  - reduce human force

concrete examples

• hydraulic press
  - hydraulic jack
  - backhoe / excavator

hydraulic press

• uses two pistons of different size
  - multiplies force using fluid pressure
  - used for stamping compacting materials

hydraulic jack

• lifts vehicles with minimal effort
  - uses fluid pressure and piston system
  - common in auto repair shops

hydraulic jack diagram

• small piston
  - fluid chamber
  - large piston lifting a car

backhoe/ excavator

• uses multiple hydraulic cylinders
  - controls arm and bucket motion
  - combines power and precision