enter a momentumless state

verb phrase

1. In physics, to reach a condition in which a body or system has zero total momentum — either it is completely at rest, or its momenta cancel each other out.

   C1

   intransitive; enter + a + adjective + statetechnical

   • "After the collision, the two blocks enter a momentumless state and stop moving."B2
   • "Once the engine stopped, the spacecraft entered a momentumless state relative to the surrounding frame."C1
   • "The particle can enter a momentumless state only if the forces acting on it balance exactly."C1
   • "Viewed from the centre-of-mass frame, the system enters a momentumless state by definition."C2

2. Figuratively, to reach a point where there is no forward drive, progress or motivation left; to stall completely.

   C1

   intransitivefigurative, rare

   • "The project entered a momentumless state after the funding was cut."B2
   • "A team that loses its best players can enter a momentumless state for months."C1