2.1.1 First-class levers

• A first-class lever has the fulcrum located between the load and the effort.

  True
• What is the fixed point around which a lever rotates called?

  Fulcrum
• The fulcrum is the fixed point around which the lever rotates.


  True
• A second-class lever has the load positioned between the fulcrum and the effort
• What is the primary advantage of using a lever?

  Mechanical advantage
• What is the purpose of a lever in amplifying force or increasing speed?

  Mechanical advantage
• The fulcrum of a lever is the pivot point around which the lever rotates
• The lever rotates around the fulcrum with the load on one end and the effort applied on the other
• In a first-class lever, a load closer to the fulcrum requires less effort
• Match the lever class with its fulcrum position:

  First-class ↔️ Between load and effort

  Second-class ↔️ Between fulcrum and load

  Third-class ↔️ Between fulcrum and effort
• What is a lever defined as?

  A rigid bar rotating around a fixed point
• Match the first-class lever example with its components:

  Scissors ↔️ Fulcrum: Joint, Load: Object being cut, Effort: Hand force

  Neck extension ↔️ Fulcrum: Atlanto-occipital joint, Load: Head, Effort: Muscles at the back of the neck

  Crowbar ↔️ Fulcrum: Fixed point, Load: Weight being moved, Effort: Force applied to the bar
• In a lever, the weight or resistance being moved is called the load
• Match the class of lever with its characteristics:

  First-class ↔️ Fulcrum between load and effort

  Second-class ↔️ Load between fulcrum and effort

  Third-class ↔️ Effort between fulcrum and load
• Where is the effort located in a third-class lever?

  Between fulcrum and load
• The neck extension is an example of a first-class lever where the atlanto-occipital joint acts as the fulcrum
• Arrange the parts of a first-class lever from top to bottom in a diagram:

  1️⃣ Load

  2️⃣ Fulcrum

  3️⃣ Effort
• The mechanical advantage of a lever is determined by the relationships between its components.


  True
• In a first-class lever, the fulcrum is located between the load and the effort.


  True
• Match the human body examples of first-class levers with their components:

  Neck Extension ↔️ Load: Head, Effort: Neck muscles, Fulcrum: Atlanto-occipital joint

  Elbow Extension ↔️ Load: Forearm, Effort: Triceps, Fulcrum: Elbow joint

  Ankle Dorsiflexion ↔️ Load: Foot, Effort: Tibialis anterior, Fulcrum: Ankle joint
• If the effort is further from the fulcrum in a first-class lever, the mechanical advantage increases.


  True
• First-class levers provide variable mechanical advantage depending on the fulcrum's position
• The three parts of a lever are load, effort, and fulcrum
• Arrange the components of a first-class lever from left to right:

  1️⃣ Load

  2️⃣ Fulcrum

  3️⃣ Effort
• What is the force applied to move the load in a lever called?

  Effort
• What is an example of a first-class lever?

  Scissors
• In a first-class lever, the fulcrum is always between the load and the effort.


  True
• In neck extension, the head acts as the load and the muscles at the back of the neck provide the effort.


  True
• A lever is a simple machine consisting of a rigid bar that rotates around a fixed point called the fulcrum
• Arrange the main parts of a lever in the correct order of rotation from effort to load.

  1️⃣ Effort

  2️⃣ Fulcrum

  3️⃣ Load
• First-class levers in the human body have the fulcrum located between the load and the effort
• The mechanical advantage of a first-class lever depends on the relative positions of the load, effort, and fulcrum.


  True