Question

Both a pair of scissors and a pair of pliers belong to the same class of levers. Name the class of lever. Which one has the mechanical advantage less than 1 ?

• A. They belong to class I lever, pair of pliers has a mechanical advantage < 1
• B. They belong to class II lever, pair of pliers has a mechanical advantage < 1
• C. They belong to class III lever, pair of pliers has a mechanical advantage < 1
• D. They belong to class I lever, scissors have a mechanical advantage < 1

Answer 1

The correct option is D

They belong to class I lever, scissors have a mechanical advantage < 1

A pair of scissors and a pair of pliers both belong to class I lever as fulcrum is in between effort and load.
Load arm of a pair of pliers is shorter than the effort arm, so a pair of pliers has mechanical advantage greater than 1.
Load arm of a pair of scissors is longer than the effort arm, so a pair of scissors has mechanical advantage less than 1.