a) The first class lever: In this type of lever, the fulcrum in the middle, the force is applied on one side of the fulcrum and the resistance on the other.
When the upper limb strengthens at the elbow,
the forearm bones are the rigid bar, the hand that moves against
the resistance by pulling something heavy is the resistance, and the elbow joint is the fulcrum. The triceps muscle, located on the posterior side of the arm does the force.
B) A
third-class lever in the upper limb is formed when the radio and the ulna
bones are the rigid bar of the lever, the elbow joint is the fulcrum, the hand moves against the resistance provided by its weight, and the force is
done by muscles like the biceps . This is a third class lever because the parts
of this lever are arranged in the sequence resistance(hand)-force(muscles)-fulcrum(elbow). This type of lever also exists in the mandibular bone. Since this may be more complicated to understand, i attached a photo.
