Work and energy theorem question

[slil]

Homework Statement

a 73kg skier coasts up a hill inclined at 9.3 degrees to the horizontal. friction is negligible. Use the work and energy theorem to determine how far along the hill the skier slides before stopping, if the initial speed at the bottom is 4.2m/s

Homework Equations

w=Ek (i think)

The Attempt at a Solution

not really sure how to start it

 

[UVW]

We always should start off work-energy problems by choosing a system. In this case, it seems to me that you intuitively chose the skier to be your system. I like this choice.

Now, for the work-energy theorem, we need to find the work done on the skier, as well as the change in energy of the skier. What force(s) is/are doing work in this situation?