This simulation helps the user to see what is meant by the ‘perpendicular distance to the pivot’, and so helps him to calculate turning moments correctly.
The "turning moment" of a force (sometimes simply called 'moment' or 'torque') is defined as the product of the force and the perpendicular distance to the pivot.
It is also possible to calculate the moment by first resolving the force into its two components: perpendicular to the bar and parallel to it. The Parallel component will be pointing either directly towards or directly away from the pivot, and so will have no turning effect. It is the perpendicular component that will have a turning effect.
Using moments it is possible to calculate loads and forces even in systems where there is no pivot! In equilibrium all clockwise moments are balanced by counter-clockwise moments. An 'imaginary' pivot can be placed anywhere inside or outside the object and the clockwise moments about this imaginary pivot will balance with the counter-clockwise ones if the system is in equilibrium!
Examples of balanced moments are everywhere: A ladder resting against a wall, a trestle table, the span of a bridge...
Gases 14.1
Page No