When I use a lever, I can lift heavier stuff. Where exactly does that additional force come from? Was it inside me all the time, or does it come from somewhere outside of me?

Question

When I use a lever, I can lift heavier stuff. Where exactly does that additional force come from? Was it inside me all the time, or does it come from somewhere outside of me?

In: Physics

Answer 1

In a lever, there are three forces. These forces all add up to zero. There is the force applied by your hand, the force applied to your object, and the force applied by the fulcrum. The force applied by your hand and the reaction of the force applied to the object (the object pushing back on the lever) are both in the same direction in a see-saw-type lever. The force from the fulcrum is what keeps the lever from being flung off in this direction.

So, not only does the additional force to lift the object come from the fulcrum, but *all* of the force to lift the object *plus* the force to keep your hand from moving come from the fulcrum.