Work Done on an Incline (highschool level)

Question

A girl pushes a 20.0 kg box, initially at rest, up a friction-less 10.0m long ramp inclined 30.00 degrees above the horizontal. If the final velocity of the box at the top of the ramp is 1.00 m/s, what was the work done on the box by the girl?

(Ans: 991J)

Answer 1

Because there is no friction and the problem gives a final velocity and indirectly an increase in height, we should use an energy approach:

Work done on the box = Kinetic energy gain + Potential energy gain (v_i = 0 and h_i = 0)

Work = (1/2)mv² + mgh

The only other piece of information is that h = dsinθ = 10 m * sin 30° = 5 m