How could Class III Levers till be considered Levers at all?

[ELLE_AW]

I thought the definition of a Lever was a machine that will decrease the force needed to do work by increasing distance. Since Class III levers always have a mechanical advantage less than 1, and they actually increase the force needed, how could they be considered levers at all? I don't get it.

 

[Dale]

Does changing the classification change the physics? The useful kinds of classifications are ones that guide you to use appropriate equations.

That said, I have never seen that definition of a lever and I don’t think it is a particularly good definition since it would apply to hydraulics also. I think that this is a rather trivial concern based on a poor definition.

 

[A.T.]

It seems to go against the definition.

Your definition of a lever is not very useful then. And the classifications of levers in general depend on the reference frame and what you consider the pivot, which is kind of arbitrary.