Question

the elbow is considered a third class lever because
a. the effort is applied further from the fulcrum than the load
b. the effort is applied closer to the fulcrum than the load
c. the fulcrum is in the center of the lever
d. the elbow is used to lift objects
please select the best answer from the choices provided.

Explanation:

To determine why the elbow is a third - class lever, we recall the definition of a third - class lever: In a third - class lever, the effort is applied between the fulcrum and the load, which means the effort is closer to the fulcrum than the load.

• Option A: In a third - class lever, the effort is not further from the fulcrum than the load. So A is incorrect.
• Option B: This matches the definition of a third - class lever (effort between fulcrum and load, so closer to fulcrum than load).
• Option C: A lever with the fulcrum in the center is a first - class lever (like a seesaw), not a third - class lever. So C is incorrect.
• Option D: The fact that the elbow is used to lift objects is not the reason it is a third - class lever. The classification is based on the relative positions of fulcrum, effort, and load. So D is incorrect.

Answer:

B. the effort is applied closer to the fulcrum than the load