A lever transfers a turning effect through a rigid arm about a pivot. A longer perpendicular effort distance can provide the required moment with a smaller effort force. Interlocking gears transmit turning effects; adjacent gears rotate oppositely, and a larger driven gear turns more slowly with a larger turning effect in an ideal system. Example: Explain a lever lifting a load with small effort. The effort acts farther from the pivot, providing sufficient balancing moment. Check your reasoning.