what is meant by force constant?

Question

it's the very last info i need for my research work in physics. of all the 30 terms i need, that's the only one i can't find!

which context? gee. i don't know either. that's why i'm asking. i was expecting an answer. not a question. it would be nicer if you said "I don't know, and I have no plans of looking it up"

Answer 1

Essentially the term FORCE CONSTANT is used to describe proportionality constant in a force equation.

I wonder in what context this term is being used? For example gravitational force constant is say kg and is used in an equation describing the force between two masses
F=kg(M1M2)/r^2
Where
kg - gravitational force constant
M1, M2 – masses
r – distance between masses

Similarly
ke in Coulomb’s Law
F=ke(Q1Q2)/r^2

Or
ks spring constant
F=ksX

X- displacement within elastic limit.

and so on.

Answer 2

What is meant by the force constant between molecules? Discuss how this microscopic quantity can be related to the measurable quantity of the substance?
6 marks

Intermolecular force exists between molecules. When two molecules are pulled apart, the restoring force f is proportional to the change in separation Dr.
Mathematically,

The proportional constant is called the force constant between molecules. 1
1
Consider a wire made up of layers of molecules. In each layer, there are N molecules each of diameter ro. The cross-sectional area of the wire is

Suppose the applied force on the wire is F. The adjacent layers of molecules are pulled apart by a small distance Dr. The stress is
1
The strain is
1
Thus, the Young Modulus of the substance is
1
This equation bridges the macroscopic and microscopic worlds: the Young Modulus being a measurable quantity and the force constant between molecules being a microscopic quantity.

Answer 3

Chemical bond force constant, determined by vibration-rotation spectrum of a given molecule (see ref.).
Others are:
Spring force constant: spring stiffness measured as force/deflection
Coulomb force constant: coefficient of friction