There is a spring of constant

which rests on an slope inclined at an angle of

to the horizontal. The coefficient of friction of the slope is

. A block of mass

compresses the spring by a distance

, and when the block is released, travels a distance

up the slope.
In terms of the other variables and

,
a) Find

.
b) Find

, the distance the spring will be compressed when the block returns to the spring.
(For those who don't do specialist,

)
The only units are

,

,

,

.
There are many variations and evil things which could be added to this question (if it's not evil enough), and I might later... :knuppel2: