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hihiip201

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Hi guys:Imagine a spring and and damper in parallel, connected to the ground on the right, and connected by a node on the left.I never quite understand why it is said that the forces between the two must be zero.According to my professor and the textbook, it is because the node has no mass, so the forces between them has to be zero.

But picturing a real life example where masses are being modeled as node by being relatively small compare to the damp coefficient as well as the stiffness of springs.

How does it tell us that the forces exerted on this mass on both side have to be zero? I mean surely F= ma and if m goes to zero then Fnet = 0. But isn't that under the assumption that a is finite?Also, if a small mass is a node, how should i go about trying to visualizing this? I am trying to think of the "wires" connecting mechanical elements as a whole bunch of connected small masses but that's not very helpful.

to me F is the cause, and a is the effect, when two springs, or a damper and spring connected together in parallel or series I don't think " how forces must be equal". instead I think of "How great the acceleartion have to be"

thank you

But picturing a real life example where masses are being modeled as node by being relatively small compare to the damp coefficient as well as the stiffness of springs.

How does it tell us that the forces exerted on this mass on both side have to be zero? I mean surely F= ma and if m goes to zero then Fnet = 0. But isn't that under the assumption that a is finite?Also, if a small mass is a node, how should i go about trying to visualizing this? I am trying to think of the "wires" connecting mechanical elements as a whole bunch of connected small masses but that's not very helpful.

to me F is the cause, and a is the effect, when two springs, or a damper and spring connected together in parallel or series I don't think " how forces must be equal". instead I think of "How great the acceleartion have to be"

thank you

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