What is the relationship of input and output forces in a mechanical advantage system?

• A. MA = Input force - Output force
• B. MA = Output force x Input force
• C. MA = Output force / Input force
• D. MA = Input force / Output force

Answer: (C)

Mechanical advantage shows how much the input effort is amplified into a larger output force. It is the ratio of the force you get on the load to the force you apply yourself. In an ideal, frictionless system, this ratio stays constant and equals how many times your input is increased. So the relationship is MA = output force / input force. This means if you push with 50 N and the system outputs 200 N, the MA is 4. The other forms would imply subtracting forces, multiplying forces, or inverting the ratio, none of which describe the amplification factor.