According to conservation of momentum, when two objects collide, the momentum lost by one object equals the momentum gained by the other. Give a common-sense, non-mathematical explanation of the connection between Newton’s 3rd law and momentum conservation. In other words,make an argument that Newton’s 3rd law and momentum conservation, though they seem different on the surface, actually “say” similar things. Again, we’re looking for conceptual, commonsense reasoning, not formal mathematical reasoning.

Question

According to conservation of momentum, when two objects collide, the momentum lost by one object equals the momentum gained by the other. Give a common-sense, non-mathematical explanation of the connection between Newton’s 3rd law and momentum conservation. In other words,make an argument that Newton’s 3rd law and momentum conservation, though they seem different on the surface, actually “say” similar things. Again, we’re looking for conceptual, commonsense reasoning, not formal mathematical reasoning.

Answer 1

Newton's 3rd law states that for every action, there is an equal and opposite reaction. This means that whenever an object exerts force on another object, the second object exerts an equal and opposite force back on the first object.

Now, let's consider the concept of momentum. Momentum is the measure of an object's motion and is determined by both its mass and velocity. When two objects collide, they exert forces on each other.

According to Newton's 3rd law, the first object exerts a force on the second object, and in response, the second object exerts an equal and opposite force on the first object. These two forces are known as action and reaction forces.

Now, let's think about how momentum is affected by these forces. When the first object exerts a force on the second object, it imparts some of its momentum to the second object. Similarly, when the second object exerts an equal and opposite force on the first object, it transfers some of its momentum to the first object.

In this way, the momentum lost by one object due to the force exerted on it is equal to the momentum gained by the other object due to the force it exerts. This is momentum conservation in action.

So, although Newton's 3rd law and momentum conservation might appear different on the surface, they are inherently connected. Newton's 3rd law describes the equal and opposite forces at play during a collision, while momentum conservation explains the transfer of momentum between the colliding objects. Both concepts ultimately "say" the same thing: that the momentum lost by one object equals the momentum gained by the other object during a collision.