Question

initially a ball has a momentum of +23 kg m/s. after an interaction, the ball has a momentum of -12 kg m/s. do we have conservation of momentum? no outside force acted on the system. momentum is conserved. momentum is not conserved.

Explanation:

Conservation of momentum applies to a closed system (no external forces), and the total momentum of the entire system remains constant. Here, only the ball's momentum is measured, but during the interaction, the ball must be part of a larger system (e.g., interacting with another object). The change in the ball's momentum means momentum was transferred to/from another part of the system, not that momentum is lost. The question does not state external forces acted, so the system's total momentum is conserved.

Answer:

Momentum is conserved.