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

AI Thread Summary
The discussion centers on the impact of a spring's direction of acceleration on the momentum of a system consisting of two gliders. It is acknowledged that an external force, such as gravity, does positive work, resulting in a positive change in momentum. However, the role of the spring is debated, with uncertainty about whether it should be considered part of the system or an external force. The direction of the spring's acceleration is noted to be negative, raising questions about its effect on total momentum. Ultimately, without a defined mass for the spring, it is suggested that it cannot contribute to the momentum of the gliders.
Joe Armas
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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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What is 'the system?' Is it both blocks or one block? Do you see how the answer is different in either case?
 
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.
 
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.
 
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