Which of the following is an example of a 3rd class lever?

In biomechanics, a third-class lever is characterized by the effort being applied between the fulcrum and the load. In this configuration, the force exerted to move the load is situated closer to the load than to the fulcrum.

Tweezers exemplify this principle effectively. When you use tweezers, the pivot point (fulcrum) is located at one end (the point where the tweezers pivot), while the load (the object being grasped) is at the other end. The effort applied by your fingers takes place in between the fulcrum and the load. This arrangement allows for a greater range of motion and speed of the load, which is a distinctive characteristic of third-class levers.

In contrast, the other choices represent different classes of levers. A wheelbarrow is a classic example of a second-class lever, where the load is between the effort and the fulcrum. A seesaw functions as a first-class lever with the fulcrum in the middle and the effort on one side and the load on the other. A crowbar also represents a first-class lever where the fulcrum is positioned between the effort applied to lift an object and the load being lifted.