Question

What is conserved when two objects collide in a closed system

Answer 1

Answer: Momentum

Explanation:

The momentum (linear momentum) $p$ is defined as mass in motion and is given by the following equation:

$p=m.v$

Where $m$ is the mass and $v$ the velocity.

Now, according to the conservation of momentum law:

"If two objects or bodies are in a closed system and both collide, the total momentum of these two objects before the collision will be the same as the total momentum of these same two objects after the collision".

Of course, the momentum of each object may change after the collision, however, the total momentum of the system does not change.