OAR Mechanical Comprehension Practice Test 2025 - Free Mechanical Comprehension Practice Questions and Study Guide

A lever operates based on the principle of moments, which states that when a lever is in equilibrium, the sum of the moments (force times distance from the pivot) about the fulcrum is equal on both sides. This principle allows a smaller force applied over a longer distance to balance a larger force applied over a shorter distance.

The lever amplifies the input force, providing a mechanical advantage that enables a user to lift heavy objects with less effort. This relationship between the distances from the fulcrum and the forces applied is central to understanding how levers function in practical applications.

While acceleration, conservation of energy, and torque are related concepts in physics, they do not specifically describe the operational mechanism of a lever. The principle of moments specifically addresses the lever's ability to balance forces around a pivot point, making it the correct concept to characterize how a lever operates.