Demonstration that classical teaching of force of effort for 2nd and 3rd class levers is erroneous

Demonstration that classical teaching of force of effort for 2nd and 3rd class levers is erroneous.

In our first manual, we demonstrated that there was functionally no such thing as a 2nd class lever. We have since learned that there are teachers who still want to use classic instruction because they think that this methodology is still valid for teaching force of effort. We will now demonstrate that this is erroneous teaching.

Note! The secret to the proof will be the application of Benedetti's discovery of the effective lever arm in 1599 as it applies to the principle of rotation (torque).

The difference between 2nd and 3rd class lever systems begin by teaching that levers are structurally defined relative to the placement of the fulcrum (F), force of effort (E) and force of resistance (R).

Classical teaching next moves to emphasizing functional importance by first demonstrating that force of effort is determined by the ratio of the effective effort arm to the effective resistance arm (the Principle of Equilibrium of Rotation).
The first formula taught leading to proof of the above statement is:
Force of effort x Effective effort arm (measured length) = Force of resistance x Effective resistance arm (measured length).
The second formula derived from the above formula is:

Force of effort = Force of resistance x Effective resistance arm Effective effort arm

Demonstration that classical teaching of force of effort for 2nd and 3rd class levers is erroneous

Demonstration that classical teaching of force of effort for 2nd and 3rd class levers is erroneous.

In our first manual, we demonstrated that there was functionally no such thing as a 2nd class lever. We have since learned that there are teachers who still want to use classic instruction because they think that this methodology is still valid for teaching force of effort. We will now demonstrate that this is erroneous teaching.

Note! The secret to the proof will be the application of Benedetti's discovery of the effective lever arm in 1599 as it applies to the principle of rotation (torque).

The difference between 2nd and 3rd class lever systems begin by teaching that levers are structurally defined relative to the placement of the fulcrum (F), force of effort (E) and force of resistance (R).

Classical teaching next moves to emphasizing functional importance by first demonstrating that force of effort is determined by the ratio of the effective effort arm to the effective resistance arm (the Principle of Equilibrium of Rotation).
The first formula taught leading to proof of the above statement is:
Force of effort x Effective effort arm (measured length) = Force of resistance x Effective resistance arm (measured length).
The second formula derived from the above formula is: