What term refers to mechanical devices that reduce the force required to do work, without changing the amount of work?

• A. Machines
• B. Engines
• C. Pulleys
• D. Levers

Answer: (A)

When you think about work, it equals force times distance. A device that makes it possible to do the same amount of work but with less applied force does so by letting you apply the force over a longer distance. The term for these mechanical devices is machines. They give you mechanical advantage, trading a larger distance (and smaller force) for the same total work done (ignoring energy lost to friction).

Pulleys and levers are examples of machines, since they’re specific ways to gain that advantage. Engines, on the other hand, are about converting energy into useful power, not primarily about reducing the input force for the same amount of work.