Question

What are the units for the spring constant, k?

Answer 1

i dont think the constant has units perse. It tends to be there to smooth out the equation.

6lb = 8 inches has no real meaning. so we need a constant of variation to make sense of the relation.

if anything it would prolly just be a suitable lb to inches; or joules to meters, or whatever it is your relating

Answer 2

That is what i was going to say amistre64

Answer 3

ive been practicing my mindreading skills lol

Answer 4

lol i SEE

Answer 5

You are wrong guys! The unit of spring constant is N/m.
It is easy to see that
F = -kx
or
[N] = [k][m]
[k]=[N/m]

Answer 6

@leonice17

Answer 7

@ArchiePhysics is right.
Spring constant gives you the force exerted by the spring per unit (change in) length

Answer 8

im wrong ? im sure its possible. But, how is your response different from: "if anything it would prolly just be a suitable lb to inches; or joules to meters, or whatever it is your relating"

Answer 9

I'm not talking about general case I'm talking about spring constant, and it has unit. Although most constants(if not every) in physics as Avogadro's, Planck's, Permittivity, Boltzmann's and many others have units. I even can't remember any of them not having unit.

Answer 10

but the units are defined, if anything, to relate the what your weighing or forcing (pick a unit of mass or weight or applied force), to some length (pick a unit of displacement) that the spring stretches. So, to say that it is in units of N/m and that "you guys are wrong!" seems a bit restricting to me, not to mention a little rude ...

why not define it in dollars to feet? k = 5dollars/3feet ; its relative to how your units are defined to begin with

Answer 11

I think you are confusing conversion factors with constants.

Answer 12

.. it possible :)

Answer 13

Sorry! If I was rude )

Answer 14

ill live ;) but if im wrong I like to know why. And if there is a difference in conversion factors to constants, then I will cede to the better.

Answer 15

Conversion factors used to convert the same amount of physical quantity between different scales but WITHIN the SAME UNIT. While constants usually supplement laws of physics by missing QUANTITIES, which have its OWN UNITS.

Answer 16

@amistre64 Are you satisfied with this explanation?

Answer 17

it is a more cogent response, yes.

one definition I came across for a conversion unit is: "A conversion factor is required to relate these two independent primary dimensions".

http://www.me.mtu.edu/~jstallen/courses/MEEM4200/lectures/energy_intro/Review_unit_systems.pdf

Which is what I have always considered a constant of variation to be, a conversion factor between 2 distinct dimensions. Since the k involved changes to fit the circumstances involved, I have always viewed it as a conversion factor and not a universal constant as in E=mc^2 where c^2 is a constant that supplies a missing quantity that has its own unit of measure.

Answer 18

"... the slope of the line will be equal to the spring constant, k, whose standard metric units are N/m." - http://www.utc.edu/Faculty/Harold-Climer/Sconstantlab.pdf

So I would agree the N/m are the standard units for it; but I cant see that it is the only units that it can be defined in.

Answer 19

You are right that it is not the only unit that it can defined in. But changing N/m to
\[kg/s ^{2} or J/m ^{2} \] does not make a big difference you even don't change the scale of a quantity, you just change its name.

Answer 20

I meant to say what ArchiePhysics said lol JK