Mass points of a Mass-spring model
Say I have a spring like the one in the picture below:
The point at the top is fixed to a ceiling.
The red coloured arrow is the direction in which I pull the spring to, and its vector is $(3, 6)$. Let's say the triangluar spring is equilateral and gravitational force is considered to be as $mg$.
Now, I want to find its restorative force in the y-axis direction. Based on Hooke's Law,
where $k$ is stiffness.
But I am not sure if I did this correctly.
Do I have to include the force of $-6k$, which is the change in length from the pulled direction vector in the y-axis?