Does density of a medium affect the conservation of momentum?

In summary: Therefore, the object's velocity does not increase to conserve momentum.In summary, the velocity of a body does not increase when it travels through a continuously less dense medium in order to conserve momentum. Momentum is still conserved, but the velocity of the object does not increase as the resistance from the less dense medium is always acting to slow it down. The medium exerts a force on the object to slow it down, but this force is offset by an equal and opposite force on the particles of the medium, which carry the lost momentum.
  • #1
JerryF
9
1
Hi all,

If a body has a given initial momentum and then travels through a continuously less dense medium would it's velocity increase to conserve momentum?

Thanks
Jerry
 
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  • #2
No
 
  • #3
JerryF said:
Hi all,

If a body has a given initial momentum and then travels through a continuously less dense medium would it's velocity increase to conserve momentum?

Thanks
Jerry
Momentum is typically not conserved for a body moving through a medium, as it will be subject to a resisting force. As it moves to a less dense medium it may decelerate less, but it cannot speed up without an external force to accelerate it.
 
  • #4
JerryF said:
If a body has a given initial momentum and then travels through a continuously less dense medium would it's velocity increase to conserve momentum?
No.
The resistance from the medium may become less as the medium comes less dense, but that resistance is always opposed to the direction of motion so always acts to slow the object and reduce its momentum.

Momentum is still conserved however. The medium exerts a force on the object to slow it, but by Newton's third law there is an equal and opposite force acting on the particles of the medium. At least some of these end up moving in the same direction that the object was moving, and these carry the momentum that the object lost.
 
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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, unless acted upon by an external force.

2. Why is conservation of momentum important?

Conservation of momentum is important because it helps us understand and predict the motion of objects in a closed system. It also plays a crucial role in many areas of physics, including mechanics, thermodynamics, and electromagnetism.

3. How does conservation of momentum apply to collisions?

In collisions, the total momentum of the objects involved before the collision is equal to the total momentum after the collision. This means that the sum of the momenta of the objects remains constant, even if the objects change direction or speed.

4. Can conservation of momentum be violated?

No, conservation of momentum is a fundamental law of physics and cannot be violated. However, it may appear to be violated in certain situations due to external forces that are not taken into account.

5. How is conservation of momentum related to Newton's third law?

Newtons's third law states that for every action, there is an equal and opposite reaction. This means that when two objects collide, the forces they exert on each other are equal and opposite. This leads to the conservation of momentum, as the total momentum of the system remains constant due to the equal and opposite forces canceling each other out.

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