If a lever has an effort arm twice as long as the resistance arm, what is the theoretical mechanical advantage?

• A. 1/2
• B. 1
• C. 2
• D. 4

Answer: (C)

Mechanical advantage for a lever is the ratio of the effort-arm length to the resistance-arm length, assuming an ideal lever with no friction. If the effort arm is twice as long as the resistance arm, the ratio is 2 to 1, giving a theoretical mechanical advantage of 2. This means you would need only half the input force to lift the same load (ignoring friction).