What force causes the flyweights of a mechanical governor to move?

The movement of the flyweights in a mechanical governor is primarily caused by centrifugal force. As the governor spins, typically connected to an engine or turbine, the rotational motion generates this outward force as a consequence of the mass of the flyweights. When the speed of the engine increases, the flyweights experience a greater centrifugal force, causing them to move outward. This change in position affects the governor's mechanism, which subsequently adjusts the fuel supply or other engine parameters to control the speed of the engine.

Centrifugal force plays a crucial role in the design and operation of mechanical governors, allowing them to function effectively in maintaining a stable speed in various running conditions.