A lever is classified according to the position of which three components?

• A. Fulcrum, effort, and load
• B. Shaft, gear, and bearing
• C. Input, output, and efficiency
• D. Arm, lever, and load

Answer: (A)

A lever is classified by how the fulcrum, the input force (effort), and the resisting force (load) are positioned relative to each other. This arrangement determines the lever’s class and its mechanical advantage. If the fulcrum sits between the effort and load, it’s a first-class lever; if the load sits between the fulcrum and the effort, it’s a second-class lever; and if the effort sits between the fulcrum and the load, it’s a third-class lever. So the best description of what defines a lever’s class is the relationship among the fulcrum, the effort, and the load. The other options refer to parts or concepts that aren’t used to classify levers.