A wooden block slides 3m up a rough plane inclined at 30∘ to the horizontal. A rope pulls the block up the plane parallel to the surface, while kinetic friction acts down the plane. The normal reaction is perpendicular to the surface.
a. (i) State the sign of the work done by the tension in the rope.
b. (ii) State the sign of the work done by friction.
c. (iii) State the sign of the work done by the normal reaction.