Which lever class never has a mechanical advantage greater than 1.0?

• A. First-class lever
• B. Third-class lever
• C. Second-class lever
• D. Wedge

Answer: (B)

Mechanical advantage depends on where you apply effort relative to the fulcrum and where the load sits. In a third-class lever, the effort is applied between the fulcrum and the load, so the effort arm is shorter than the load arm. Since mechanical advantage is the ratio of the effort-arm length to the load-arm length, that ratio is always less than one. So you don’t get a lever that multiplies your force; you get more speed and a larger range of motion instead. Common examples are using your forearm during a bicep curl or tweezers, where the hand moves faster than the load. By contrast, a second-class lever has a longer effort arm than load arm (MA > 1), and a first-class lever can have MA either greater or less than 1 depending on distances. A wedge isn’t a lever.