Question

1. how do you define the law of conservation of momentum?

for a collision occurring between object a and object b in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.
for a collision occurring between object a and object b in an open system, the total momentum of the two objects before the collision is less than the total momentum of the two objects after the collision.
for a collision occurring between object a and object b in an open system, the total energy of the objects before the collision is greater than the total energy of the two objects after the collision.
for a collision occurring between object a and object b in an open system, the total momentum of the two objects before the collision is greater than the total momentum of the two objects after the collision.

Explanation:

The law of conservation of momentum states that in an isolated system (a system with no external forces acting on it), the total momentum of the system remains constant. When two objects collide in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.

Answer:

For a collision occurring between object A and object B in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.