Understanding conservation of momentum

In summary, conservation of momentum is a fundamental rule of nature that is derived from the translational symmetry of the universe, which states that the laws of physics are the same at any point in space. This is based on Noether's theorem, which states that for every symmetry, there is a conserved quantity related to motion in that direction. Similarly, conservation of angular momentum and energy can be derived from rotational and time translation symmetries, respectively.
  • #1
jd12345
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Is conservation of momentum a fundamental thing? For example :- conservation of energy is basic, its fundamental, it has no answer of why it is conserved. Its just a rule of nature

So in the same way, is conservation of momentum a rule of nature or does it have a deeper reason?
And Newtons laws are basically derived from conservation of momentum right?
 
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  • #2
It sure does have a deeper meaning. Conservation of momentum can be derived from translational symmetry of the universe, based on Noether's theorem. Translational symmetry means that the laws of physics at one point in space are the same as the laws of physics at another point in space. This is a cosmological principle-- an assumption that we are not at a special place in the universe, and every place in the universe is equally special. Noether's theorem states that for every symmetry, you get a conserved quantity having to do with motion along the direction of symmetry. We also get conservation of angular momentum from rotational symmetry of the universe (physics don't depend on which way you are facing) and conservation of energy from time translation symmetry. (It's harder to explain why energy is motion in time.)
 

1. What is conservation of momentum?

Conservation of momentum is a fundamental principle in physics that states that the total momentum of a closed system remains constant over time. This means that the combined momentum of all objects in the system will not change unless acted upon by external forces. In other words, momentum is conserved in all physical interactions.

2. How is momentum defined?

Momentum is defined as the product of an object's mass and its velocity. It is a vector quantity, meaning it has both magnitude and direction. The equation for momentum is: p = mv, where p is momentum, m is mass, and v is velocity.

3. What are some real-life examples of conservation of momentum?

There are many examples of conservation of momentum in everyday life. One example is a game of billiards, where the cue ball transfers its momentum to the other balls upon impact. Another example is a rocket launching into space, where the gases expelled from the rocket provide an equal and opposite force, preserving the total momentum of the system.

4. How does conservation of momentum relate to Newton's Third Law?

Newton's Third Law states that for every action, there is an equal and opposite reaction. This means that when two objects interact, they exert equal and opposite forces on each other. Conservation of momentum is related to this law because the change in momentum of one object is equal and opposite to the change in momentum of the other object, resulting in the total momentum of the system remaining constant.

5. Can conservation of momentum be violated?

No, conservation of momentum is a fundamental law of physics and has been proven to be true in countless experiments. In a closed system, momentum is always conserved, meaning it cannot be created or destroyed. However, in an open system where external forces are present, such as air resistance, the momentum of individual objects may change, but the total momentum of the system will still remain constant.

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