Simple Machines: Levers and Pulleys

Simple Machines

Levers

• A lever is a rigid bar or beam that pivots around a fixed point (fulcrum)
• Levers can be used to lift, push, or move heavy loads with less effort
• There are three types of levers:
  1. First-class levers: Fulcrum is between the effort and load
  2. Second-class levers: Load is between the effort and fulcrum
  3. Third-class levers: Effort is between the load and fulcrum

Pulleys

• A pulley is a wheel with a grooved rim and a rope, cable, or chain wrapped around it
• Pulleys change the direction of force or motion, making it easier to lift or move heavy loads
• There are two types of pulleys:
  1. Fixed pulleys: The pulley is attached to a fixed object
  2. Movable pulleys: The pulley is attached to the load

Screws

• A screw is an inclined plane wrapped around a cylindrical shaft
• Screws convert rotary motion into linear motion
• Examples of screws include:
  • Screwdrivers
  • Jar lids
  • Bolts and nuts

Wheels and Axles

• A wheel is a circular object that rotates around a fixed axis (axle)
• Wheels reduce friction, making it easier to move heavy loads
• Examples of wheels and axles include:
  • Cars
  • Bicycles
  • Ferris wheels

Inclined Planes

• An inclined plane is a flat surface tilted at an angle
• Inclined planes change the direction of force or motion, making it easier to lift or move heavy loads
• Examples of inclined planes include:
  • Ramps
  • Stairs
  • Ladders

Simple Machines

Levers

• Rigid bar or beam that pivots around a fixed point (fulcrum) to lift, push, or move heavy loads with less effort
• Three types of levers:
• First-class: Fulcrum between effort and load
• Second-class: Load between effort and fulcrum
• Third-class: Effort between load and fulcrum

Pulleys

• Wheel with a grooved rim and a rope, cable, or chain wrapped around it to change direction of force or motion
• Two types of pulleys:
• Fixed pulleys: Attached to a fixed object
• Movable pulleys: Attached to the load

Screws

• Inclined plane wrapped around a cylindrical shaft to convert rotary motion into linear motion
• Examples:
• Screwdrivers
• Jar lids
• Bolts and nuts

Wheels and Axles

• Circular object that rotates around a fixed axis (axle) to reduce friction and make it easier to move heavy loads
• Examples:
• Cars
• Bicycles
• Ferris wheels

Inclined Planes

• Flat surface tilted at an angle to change direction of force or motion and make it easier to lift or move heavy loads
• Examples:
• Ramps
• Stairs
• Ladders