Princeton MCAT Conten Review Math and Physics

Q: How to decipher total mechanical energy problems to Big Five Equation problems?

ie. A skier begins at rest at the top of a hill of height 125 m. If friction between her skis and the snow is negligible, what will be her speed at the bottom of the hill?

Here how would we know if its a total conservation mechanical energy problem or use the equation V2=V02+2ad?

Q2: In Mechanical Efficiency work output confuses me with different machines. With an incline its said to be the work when the machine is not used and you simply raise the mass, but with pulley and levers its the opposite side of the work input. Can anyone please explain what work output is.