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flyingpig

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## Homework Statement

It feels good to be back after spending a month in the calculus and beyond section.

Here is my question

[PLAIN]http://img97.imageshack.us/img97/3883/unleduh.jpg

Imagine a spring was pushed back by some distance [tex]x_0[/tex] and then it ends up at some distance 5m up the ramp where the dashed line, the equilibrium point is at at the top of the ramp.

Now my question is, what is x? The final distance from the equilibrium point to 5m?

My concern is that is the x in F = -kx the distance or the [tex]5cos\phi[/tex] distance because of [tex]\vec{F} \cdot \vec{dx}[/tex]?

What if I want to find work done by spring? Let's say [tex]x_0 = -4m[/tex] from the equilibrium point.

Is it

[tex]\int_{x_0 = -4}^{x = 5m} \vec{F_s} \cdot \vec{dx}[/tex] or

[tex]\int_{x_0 = -4}^{x = 5cos\phi\;m} \vec{F_s} \cdot \vec{dx}[/tex]

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