Question 2
In which direction does friction act, and what does it do?
The right answer is the one marked above.
Opposite to the motion; it obstructs the motion. Friction is the resisting force that obstructs the motion of an object moving over a surface.
So part of any force we apply is spent purely on overcoming friction. That is why nothing happens when a table is pushed gently.
The direction of friction is not fixed — it is always decided by the motion. Send the object the other way and friction turns round too.