Question

At what direction is the frictional force?

Answer 1

The frictional force is parallel to the surface, opposing the motion. So, it would be pointing down the slope, if the drawing in the arrow represents the motion.

Answer 2

Yes, the arrow represent the motion. But ummm, i'm not sure the frictional force is parallel to the surface, opposing the motion. Just like when we walk, the frictional force is in the same direction as our motion....

Answer 3

No, it's not. The friction always opposes motion.