Question about mechanics, acceleration with friction

Sorry if i sound a bit vague, currently watching a film :)

So for example if you have two connected particles, one on a slope with friction, the other dangling down, you use f=ma to work out the overall acceleration
If the rope is cut, do you use f as the resolved vector of weight (parallel to slope) minus friction to work out the acceleration?
eg mass * Sinx - friction = mass * acceleration

Exam tomorrow, just realised i'm not entirely sure about this xD

If you cut the rope,

a = g*(sinΘ - µcosΘ)

This is true for any mass