Mechanical Advantage and Lever Systems

Definition

• Mechanical Advantage: The ability of a lever system to move a large load with a small effort.
  • Achieved because the effort is further from the fulcrum than the load.

Lever Systems

• Components:
  • Fulcrum: Pivot point of the lever.
  • Load/Resistance: The weight or force to be moved.
  • Effort: Force applied to move the load.

Classes of Levers

• First-Class Lever: Fulcrum is between the effort and load.
  • Example: Seesaw.
• Second-Class Lever: Load is between the fulcrum and effort.
  • Example: Wheelbarrow.
• Third-Class Lever: Effort is between the fulcrum and load.
  • Example: Human arm.

Easy Mnemonic

• FLE 123: Use to determine the class of lever based on which component is in the middle.
  • Fulcrum, Load, Effort.

Lever System Diagrams

• Effort Arm: Distance from fulcrum to effort point.
• Resistance Arm: Distance from fulcrum to load point.
• Diagram tasks may involve drawing and labeling effort and resistance arms.

Calculating Mechanical Advantage

• Formula: Mechanical Advantage = Effort Arm / Resistance Arm
  • Be cautious of similar incorrect formulas: addition, multiplication, subtraction.

Examples and Applications

• First-Class Lever:
  • High mechanical advantage if effort arm is longer than resistance arm.
• Second-Class Lever:
  • Mechanical advantage determined by arm lengths.
• Third-Class Lever:
  • Typically low mechanical advantage as effort arm is shorter.

Exam Tips

• Identify and label lever systems and their components.
• Recognize lever class by component position.
• Understand arm length implications on mechanical advantage.
• Practice identifying which is the resistance arm (A) and the effort arm (B) in diagrams.