Finding the Transferred Energy for a Block Sliding Down a Ramp

1. The problem statement, all variables and given/known data

A 5.0kg block slides down a ramp, starting with a velocity down the slope of 2.5 m/s. The ramp is 1.5 m high and has an angle of 25 degrees. The force of friction acting upon the block is 20.0 N.

How much energy is transferred in or out by gravity, normal force, and friction respectively as it slides down the ramp?

2. Relevant equations

Ek = 1/2 mv2
Ep = mgh
Fg = 9.8m
Fn = Fgx
Ff =μFn

3. The attempt at a solution
This question is actually a five part question. I have completed parts 1 and 5, which is here in case it may be useful:
1: How much energy does the block begin with?
A: Eki= 0.5(5.0kg)(2.52) = 15.6 J
5. What is the final velocity of the block?
Ef = Ei + WFf
(0.5)(5.0kg)vf2 = (5.0kg)(9.8m/s/s)(1.5m) + (0.5)(5.0kg)(2.52m/s) – (20N)(1.5/cos(25)m)
vf = 2.69 m/s

I’m not sure what concept I’m supposed to apply to discover "energy transferred", however. I thought that the energy within a closed system remained constant. I do not want the answers; I simply want some sort of push in the right direction.

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