Does a Spring Move Upward or Downward When the Box Stops?

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When a box moving upward at a constant speed stops, the spring attached to it will initially continue moving upward due to inertia. However, the net forces acting on the spring change when the box decelerates, resulting in a downward force that ultimately leads to a downward acceleration of the spring. Despite the initial upward motion, the spring will eventually move downward after the box stops. The key takeaway is that the spring's behavior is influenced by the forces acting on it, particularly during the deceleration of the box. Understanding these dynamics clarifies the spring's movement in relation to the box's stopping.
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Homework Statement


A spring (in equilibrium) is attached to the top of a box that is moving at a constant speed vertically upward.
However, if the box stops, does the spring go upward or downward?

Homework Equations


The Attempt at a Solution



The spring goes downward because originally, the force being exerted on the spring is the spring force and gravity. But, when the box is stopping, there must be an extra downward force to slow the box down, so once the box stops, there will be a net downward force.

Logically, I would imagine the spring going upward but...

The answer is that the spring will go downwards. Is this the correct reasoning?

All replies are much appreciated.

EDIT: Sorry if I wasn't clear enough before, but the spring is inside the box and is hanging from the top of the box.
 
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collegeconfid said:
The spring goes downward because originally, the force being exerted on the spring is the spring force and gravity. But, when the box is stopping, there must be an extra downward force to slow the box down, so once the box stops, there will be a net downward force.

That's true, but a net downward force means a downward acceleration. It doesn't mean a downward speed.

Logically, I would imagine the spring going upward but...

That's correct. The spring initially keeps whatever speed it had before the box stopped, so it's still going upward when the box stops.
 
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