Input divided by output = ____________________________ ?

• A. Velocity Ratio
• B. Efficiency
• C. Ideal mechanical advantage
• D. Actual Mechanical Advantage

Answer: (C)

Think about how a simple machine transmits effort to lift a load. The ratio of how far you move the input end to how far the load moves is the distance ratio. In an ideal, frictionless system, that same distance ratio also describes how the forces relate, because no energy is lost to friction. That ideal relationship between input movement and output movement is what we call the ideal mechanical advantage. So when you see input divided by output (in terms of distances), you’re looking at the ideal mechanical advantage. In the real world, losses like friction make the actual force you must apply larger than this ideal value, so the actual mechanical advantage is lower than the ideal.