Does the spring's direction of acceleration affect the momentum of the system?

In summary, the conversation discusses the concept of net external force and its effect on the momentum of a system. The question of whether the spring in part c increases or decreases the momentum is raised, with the answer dependent on whether the system is considered to be both blocks or just one block. It is also noted that, even if the spring is considered external to the system, it cannot add or remove momentum due to its assigned mass of zero.
  • #1
Joe Armas
17
0

Homework Statement


In the pictures

Homework Equations



Fnet = dp/dt

The Attempt at a Solution



I know in part b there is a net external force (gravity) that does positive work, fnet > 0, thus dp/dt is positive. Does the spring in part c increase or decrease the momentum of the system? I am not too sure of
my answer.[/B]
0222151508.jpg
 
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  • #2
What is 'the system?' Is it both blocks or one block? Do you see how the answer is different in either case?
 
  • #3
0222151508.jpg

brainpushups said:
What is 'the system?' Is it both blocks or one block? Do you see how the answer is different in either case?
The system consists of the two gliders. So it appears that the spring is indeed an external force. But the direction the spring accelerates the block is in negative direction, so I am not sure how the TOTAL momentum of the system will change.
 
  • #4
Joe Armas said:
0222151508.jpg


The system consists of the two gliders. So it appears that the spring is indeed an external force. But the direction the spring accelerates the block is in negative direction, so I am not sure how the TOTAL momentum of the system will change.
Even if you count the spring as external to the system (and I'm not sure that's intended), you are not given any mass for it. Taking its mass as zero, it cannot add or remove any momentum from the system of gliders.
 

FAQ: Does the spring's direction of acceleration affect the momentum of the system?

What is momentum conservation?

Momentum conservation is a fundamental law of physics that states that the total momentum of a closed system remains constant over time. This means that in a closed system, the total amount of momentum before an event or interaction is equal to the total amount of momentum after the event or interaction.

Why is momentum conservation important?

Momentum conservation is important because it is a fundamental law that governs the behavior of objects in motion. It allows us to predict and understand the motion of objects and systems, and it is a crucial concept in many areas of science and engineering, such as mechanics, fluid dynamics, and thermodynamics.

How is momentum conserved?

Momentum is conserved through interactions between objects. In a closed system, the total momentum remains constant because the momentum of an object can only change if it experiences a force. This force must be balanced by an equal and opposite force, resulting in a conservation of momentum.

Does momentum conservation apply to all systems?

No, momentum conservation only applies to closed systems where there is no external force acting on the system. In an open system, where there are external forces present, momentum may not be conserved. However, the law of conservation of momentum can still be applied by considering the total momentum of the system and the external forces acting on it.

How is momentum conservation related to Newton's laws of motion?

Momentum conservation is closely related to Newton's laws of motion, specifically the law of action and reaction. This law states that for every action, there is an equal and opposite reaction. This means that when two objects interact, their total momentum remains constant, as the forces they exert on each other are equal and opposite.

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