Objective
Balance a lever with forces at different distances from the pivot and see that torque = force × lever arm, the rotational cousin of force.
The idea
A seesaw tilts when the torques on each side disagree. Move the weights, or change their size, and watch which way it tips - a longer arm makes a small weight just as strong as a heavy one close in.
Try this
- 1Put an equal weight twice as far from the pivot - which way does it tip?
- 2Rebalance it by moving the other weight further out.
- 3Compare a big force close in with a small force far out.
- 4Read the two torques and the moment of inertia of each side.
Watch for
- Torque = force × distance from the pivot (lever arm).
- The side with the larger torque wins, like two people on a seesaw.
- Equal torques on both sides cancel: equilibrium.
- Distance multiplies force, so small forces can balance big ones.