Coefficient of friction - work and energy

[h6872]

A 2 kg metal plate slides down a 10m high slope. If the slope is 49 degrees, and the speed at the bottom is 8m/s what is the coefficient of friction?

This is what I tried:
Wf = F x d
I found the work done by Eg = Ek+Wf and then found d with 10/cos49... then I tried M = Ff/Fn (Fn found by mg) but then the answer I got was wrong... I don't know what to do next! Please help me!
Thanks

[Doc Al]

I see two problems:
(1) d = 10/sin49 (not cos49)
(2) the normal force is not equal to mg, since the plate is on an incline. (Find the normal force by applying equilibrium to forces perpendicular to the incline surface.)