Which equation represents a mechanical advantage?

• A. time / distance
• B. distance / force
• C. input work / output work
• D. output force / input force

Answer: (D)

Mechanical advantage is how much a machine multiplies your input force. It’s represented by the ratio of the force the machine outputs to the force you put in: output force divided by input force. This tells you how many times bigger the force you get is compared to the force you apply.

So if you push with 10 newtons and the machine lifts or moves the load with 50 newtons, the mechanical advantage is 50 divided by 10, which equals 5. That means the machine makes your effort feel like five times less work for the same load, ignoring friction and losses.

The other expressions don’t measure force amplification. Time over distance relates to speed or velocity ratios, a different concept. Distance over force or input work over output work involves different quantities (distance or work) and doesn’t capture how much bigger the output force is than the input force.