- #1
happyparticle
- 426
- 20
- Homework Statement
- Estimate the effective spring constant (k) for this system
- Relevant Equations
- F= -kx
##F = -\frac{du}{dr}##
Hi,
First of all I hope it doesn't bother if I ask too much question.I found the values of ##u1,u2## for 2 differents posistions ##(r1,r2
)## and I now have to determine the spring constant (k).I'm thinking about using$$
F= -kx
$$
with ##F = -\frac{du}{dr}## then
$$
U = \int -kr \cdot dr =-k\frac{r^2}{2}
$$
I'm wondering if I can use ##r=r2## and ##U=U2## or I'm completely wrong by using ##F=−kx##
Otherwise, I found ##k=2\varepsilon\Big(\frac{n}{r_0}\Big)^2## Here, but I'm not sure how to get this equation from ##
U_{LJ}(r)=\varepsilon\Big[\Big(\frac{r_0}{r}\Big)^{2n}-2\Big(\frac{r_0}{r}\Big)^n\Big]
##
First of all I hope it doesn't bother if I ask too much question.I found the values of ##u1,u2## for 2 differents posistions ##(r1,r2
)## and I now have to determine the spring constant (k).I'm thinking about using$$
F= -kx
$$
with ##F = -\frac{du}{dr}## then
$$
U = \int -kr \cdot dr =-k\frac{r^2}{2}
$$
I'm wondering if I can use ##r=r2## and ##U=U2## or I'm completely wrong by using ##F=−kx##
Otherwise, I found ##k=2\varepsilon\Big(\frac{n}{r_0}\Big)^2## Here, but I'm not sure how to get this equation from ##
U_{LJ}(r)=\varepsilon\Big[\Big(\frac{r_0}{r}\Big)^{2n}-2\Big(\frac{r_0}{r}\Big)^n\Big]
##