Class III levers have mechanical advantage less than one. Why are they then used?
Class III levers have mechanical advantage less than one. Why are they then used?
The correct option is A To obtain gain in speed
In class I lever, fulcrum acts in the middle, load at one end and effort at another end.
Effort arm >, = or < load arm and mechanical advantage (MA) can be >, = or < 1.
Examples: Scissors, see-saw, hand pump.
In class II lever, the load acts in middle, fulcrum at one and effort at the other end.
Effort arm > load arm and mechanical advantage is always greater than one, hence it acts as a force multiplier.
Examples: Nutcracker, Hinged door.
In class III levers, efforts acts in middle and load and fulcrum are at the end points.
Effort arm < load arm and mechanical advantage is always less than one, but by using them we get a gain in speed, i.e. a larger movement of the load is obtained by smaller movement of effort, hence it acts as a speed multiplier.
Example: Tong, Bread knife, Foot treadle.
To obtain gain in speed
In class I lever, fulcrum acts in the middle, load at one end and effort at another end.
Effort arm >, = or < load arm and mechanical advantage (MA) can be >, = or < 1.
Examples: Scissors, see-saw, hand pump.
In class II lever, the load acts in middle, fulcrum at one and effort at the other end.
Effort arm > load arm and mechanical advantage is always greater than one, hence it acts as a force multiplier.
Examples: Nutcracker, Hinged door.
In class III levers, efforts acts in middle and load and fulcrum are at the end points.
Effort arm < load arm and mechanical advantage is always less than one, but by using them we get a gain in speed, i.e. a larger movement of the load is obtained by smaller movement of effort, hence it acts as a speed multiplier.
Example: Tong, Bread knife, Foot treadle.
