Question

when is momentum conserved?
it is conserved when only two objects collide; more than two objects cant conserve momentum.
it is always conserved.
momentum is conserved when the system is closed, which means there are no forces, like friction, acting on it.
momentum is never conserved.

Explanation:

• The first option is incorrect because momentum conservation is not limited to two - object systems.
• The second option is wrong as momentum is not always conserved. External forces can change the momentum of a system.
• The fourth option is incorrect as momentum is conserved under certain conditions.
• According to the law of conservation of momentum, momentum is conserved when the system is closed (isolated), meaning there are no external forces (like friction) acting on it.

Answer:

Momentum is conserved when the system is closed, which means there are no forces, like friction, acting on it.