Question

multiple choice question

the mechanical advantage is the ratio of ______.

• resistance arm length to input force
• a levers output force to its input force
• a levers effort arm to resistance arm length

Explanation:

Define mechanical advantage

Using the Skeletal Lever Systems knowledge point

$$ \text{Mechanical Advantage (MA)} = \frac{\text{Length of effort arm}}{\text{Length of resistance arm}} = \frac{L_E}{L_R} $$

Evaluate the given options

• Option 1: "resistance arm length to input force" compares a length to a force, which is incorrect.
• Option 2: "a lever's output force to its input force" is a general physical definition of mechanical advantage, but in the context of skeletal biomechanics and the options provided, the ratio of the lengths of the arms is the primary anatomical definition.
• Option 3: "a lever's effort arm to resistance arm length" directly matches the mathematical ratio of the effort arm length to the resistance arm length.

Answer:

• resistance arm length to input force
• a lever's output force to its input force
• a lever's effort arm to resistance arm length (Correct answer)