Lever equilibrium
Change the lever arms to balance the same load with a smaller force.
When a lever is balanced, the torques on the two sides of the fulcrum are equal in magnitude and opposite in direction. This experiment automatically calculates the effort needed to keep the lever horizontal. The longer the effort arm, the smaller the effort required, but the saving in force comes at the cost of moving the effort through a greater distance.
This is a static model: forces and the graph update as soon as you change a parameter.
Balancing effort vs. effort arm
Think about it
If the effort arm is increased to 2 times its original length, how does the effort needed for balance change?
It falls to half its original value. The load and load arm are unchanged, so the load torque G L_load stays the same; therefore F_effort is inversely proportional to L_effort.
Model assumptionsIdeal light rod · Static horizontal balance · Forces act perpendicular to the rod · g = 9.8 m/s² · Fulcrum friction neglected
Data log
Set the parameters and click “Record data”. Record several rows with different parameters to plot their relationship and fit a straight line; pause and record at different times to study how a reading changes with time.