First Class Lever

   

 

The fulcrum lies between the effort and the load.  The point on which the bar is resting is known as the fulcrum.  The bar is the lever.  The muscular power or effort alone would not move the weight.  The lever is a simple machine that concentrates the effort or force and makes it possible to perform the work.

That part of the lever between effort and fulcrum is the effort arm. That part of the lever between the fulcrum and the load is load arm.  If the load arm and effort arm were equal in length, an effort equal to the load would be required (10 pounds of effort would lift 10 pounds of load).  There would be no mechanical advantage in this lever.   When the effort arm is longer than the load arm, the effort is less  than the load and we have mechanical advantage – because the effort travels farther than the load.  Mechanical advantage (MA) is a value that tells you the number of times a machine increases the applied force.

 

The actual mechanical advantage =  Force_resistance (F_r­) /  Force_effort (F_e)

 

The ideal mechanical advantage =  Distance_effort (D_e) /  Distance_resistance (D_r)