Force done by the spring if a weight is attached

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Homework Help Overview

The discussion revolves around the force exerted by a spring when a mass is attached to it. The subject area includes concepts of forces, specifically gravitational force and spring force, as well as equilibrium conditions.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between gravitational force and spring force, questioning the signs associated with these forces. There is an attempt to clarify the conditions under which the mass is considered at rest and how that affects the forces acting on it.

Discussion Status

The discussion has progressed with participants confirming the need to consider the signs of the forces involved. There is a recognition of the equilibrium condition where the forces must cancel each other out, leading to a clearer understanding of the relationship between the forces.

Contextual Notes

Participants are discussing the implications of the mass being at rest and the corresponding forces acting on it, which includes considerations of directionality and sign conventions in their equations.

dav1d
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Homework Statement



What is the force done by the spring if an object of mass m is attached.

Homework Equations


F=ma
F=-kx
Fg=mg


The Attempt at a Solution



Sum F = 0
mg-kx=0
mg-Fs=0
Fs=mg

Therefore the force done by the spring is mg? is the +/- right? for direction? Is the force right?
 
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Properly think about it:

The mass is hanging from the spring. I assume that when it is observed, it can be considered at rest.
If it's at rest, there are only two forces acting on the mass: gravity and the spring force. Since the mass is at rest, all forces must cancel each other.
.
Since both forces are acting in opposite directions, they shouldn't have the same sign.

You stated that Sum F = 0. Therefore, Fs + Fg = 0
 
Ok so then Fs=-Fg=-mg.
Just change the sign of my answer?
 
Yep.
 
ok thank you very much! i thought the sign was a bit messed up.
 

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