The torsion bar then twists along its axis to provide the spring force.
This may be achieved by mechanical (spring force) or pyrotechnic devices.
When closed, the steam pressure acted on the small diameter and was balanced by the spring force.
This greater area overwhelmed the spring force and the valve flew completely open with a "pop".
The bolt returns forward under spring force, loading a new round into the barrel.
Conservative forces include gravity, the electromagnetic force, and the spring force.
The solenoid coil has to counteract only the spring force.
As they extend, the spring force becomes less and the take-up has less effect.
Upon release, the "spring force" of the seat propels the astronaut a tiny bit up.
Both mechanisms reduce resonance because spring force and its moving mass vary with stroke.