Question

The law of conservation of momentum states that the sum of momenta of two objects before collision is equal to the sum of momenta after the collision provided that ______.

Answer 1

Hint: One of the most well-known principles in physics is the conservation of momentum. The conservation of momentum principle states that a system's overall momentum is always conserved. Along with the conservation of energy and mass, the conservation of momentum is a fundamental idea in physics.

Complete answer:
The mass of an object multiplied by its velocity is the definition of momentum. The conservation of momentum says that the quantity of momentum remains constant inside a problem domain; momentum is neither generated nor destroyed, but only modified by the action of forces defined by Newton's equations of motion. Because momentum is a vector quantity, dealing with it is more complex than dealing with mass and energy. At the same time, momentum is preserved in all three physical directions. When dealing with a gas, it's considerably more challenging since forces in one direction might impact momentum in another due to the collisions of numerous molecules.
The law of conservation of momentum says that unless an external force is introduced, the total momentum of two or more bodies operating on each other in an isolated system remains constant.
 $ {m_1}{u_1} + {m_2}{u_2} = {m_1}{v_1} + {m_2}{v_2} $
As a result, neither the creation nor the destruction of momentum is possible. The idea of momentum conservation is a direct result of Newton's third law of motion. Newton's third law says that when an object A produces a force on an object B, object B responds with a force of the same magnitude but opposite direction. Newton derived the law of conservation of momentum from this concept.
Hence No external force is the answer.

Note:
The total momentum of the two objects before and after a collision between object 1 and object 2 in an isolated system is equal to the total momentum of the two objects after the collision. That is to say, the momentum acquired by item 2 equals the momentum lost by object 1.