Marisol pushes a 3.0 kg box 7.0 m across the floor with a force of 12 n. she lifts the box to a shelf 1 m above the ground. how much work does marisol do on the box?

                   Work = (force) x (distance)

-- Floor portion:
Force = 12 N
Distance = 7.0 m
                             Work = (12 x 7) = 21 joules

-- Lift portion:
Weight of the box = (mass) x (gravity) = (3.0) x (9.8) = 29.4 newtons
Force to lift = weight of box = 29.4 N
Distance = 1 m
                             Work = (29.4 x 1) = 29.4 joules

                       Total work on the box = (21 + 29.4) = 50.4 joules