Final answer:
In a piston engine that uses a full floating wrist pin, the wrist pin is prevented from falling out while the engine is running due to the design and components of the engine.
Step-by-step explanation:
In a piston that uses a full floating wrist pin, the wrist pin is prevented from falling out while the engine is running due to the design and components of the engine.
The full floating wrist pin is held in place by the connecting rod and the piston. The connecting rod has two ends, one end is attached to the piston and the other end is attached to the crankshaft. The wrist pin fits through holes in both the small end of the connecting rod and the piston, allowing the piston to move up and down while the wrist pin stays in place. The wrist pin is not secured to the piston or the connecting rod, but its movement is controlled by these components, preventing it from falling out.