How Far Does a Spring Stretch with a 5 kg Weight?

[JoeCho]

Homework Statement

A 5 kg weight hangs on a spring with spring constant k = 0.038 n/m. How far does the spring stretch?

Homework Equations

Fsp = -kX

Fnet = Fsp + Fg

The Attempt at a Solution

So I already know that Fsp = 0.038X and that Fnet = ma = 5 (-9.8)

So -49 = 0.038X + Fg.

But isn't the force of gravity equal to 5(-9.8) as well? Am I approaching the problem incorrectly?

 

[llello]

So the spring is hanging. Its not accelerating. Its just dangling there. So sum of forces is zero. Try that.

 

[JoeCho]

So if Fnet = 0

| Fsp
o
| Fg

Fsp + Fg = Fnet = 0

kX + mg = 0

0.038X + 5 (-9.8) = 0

0.038X = 49

X = 1289.47 Meters?

Thanks I didn't think about it not accelerating.

 

[llello]

Looks good. Didn't check numbers. Glad I could help. Good luck on your future physics endeavors.