Mechanical Advantage = output force / input force

The lever, one of the 6 simple machines, is a beam, plank, bar or other type of rigid rod usually made of wood or metal.
All levers have three parts: the fulcrum, the load (resistance) and the effort.
All levers are classified into three types (or classes).
The class of the lever is determined by which lever part is located in the middle (fulcrum, load or effort).

1st class LEVER
The fulcrum is in the middle.
Examples:
seesaw, crowbar, scissors, pliers, hammer removing a nail
Mech advantage can be less than 1, equal to 1 or greater than 1.
Changes direction of input force.

2nd class lever - resistance (load) (weight) in the middle.
nutcracker, wheelbarrow, bottle opener,
force multiplier lever
Mech advantage ALWAYS >1
Does NOT change direction.

3rd class lever - effort (or energy or force or power) in the middle.
hammer (when nailing) elbow fulcrum / hand effort / hammer head resistance
broom, hoe, baseball bat, jaw, bow and arrow, tongs, tweezers, stapler, steam shovel
speed multiplier lever
Mech advantage ALWAYS <1
Does NOT change direction.