A box is raised at constant speed by a man pulling up on a rope. During the ascent, which of the following statements is true. Assume that air resistance is negligible.

  1. The work done by all conservative forces on the box is 0.
  2. The work done by all non-conservative forces on the box is 0.
  3. The work done by all conservative forces on the box is positive.
  4. The work done by all non-conservative forces on the box is positive.