A 6 N box is projected with a velocity of 2 m/s at the bottom of the plane inclined 30 degrees above the horizontal. If friction is neglected, how high up along the plane will it travel before coming to rest?

Since friction is negligible, use conservation of potential and kinetic energies.

KE (at bottom) => PE (at top)

mv²/2 = mg*Lsin(θ)
Solve for L. I get 0.82m