Three types of Levers

Question 1

Class 1 Lever

Answer 1

Definition: A lever where the fulcrum is located between the effort (force) and the load (resistance).

Example in the Human Body: The head and neck act as a Class 1 lever when nodding.

1. Fulcrum: The neck joint (where the head pivots).
2. Effort: The muscles (e.g., trapezius muscle) that generate the force to move the head.
3. Load: The weight of the head that the muscles must lift.

allows for versatility, as it can be adjusted to gain a speed or force advantage depending on the distances between the components.

Question 2

Class 2 Lever

Answer 2

Definition: A lever where the resistance (load) is positioned between the effort (force) and the fulcrum (axis of rotation).

Example in the Human Body: The ankle joint when standing on toes.

1. Fulcrum: The ankle joint (point of rotation).
2. Effort: The gastrocnemius muscle (calf muscle) that generates the force to lift the body.
3. Load: The weight of the body (resistance) being lifted while standing on toes.

Second class levers provide a force advantage, allowing an individual to lift a larger load with relatively less effort, similar to how a wheelbarrow works.

Question 3

Class 3 Lever

Answer 3

Definition: A lever where the effort (muscular force) is located between the fulcrum (joint) and the resistance (load).

Example in the Human Body: Biceps curl.

1. Fulcrum: The elbow joint (point of rotation).
2. Effort: The biceps muscle (force applied to move the forearm).
3. Load: The weight (resistance) held in the hand being lifted.

Third class levers provide a speed advantage, allowing movement with light resistance through a greater range of motion. Common examples include squash racquets, cricket bats, and snow shovels.