Friction Between Box and Rug

Think about the situation described below. A number of questions based on this situation are posed afterwards, each having 2 possible responses (LEFT or RIGHT). We'll do some (but probably not all) of these questions in the lectures when you will all be asked to vote on which answer you think is correct. (Soon afterwards, you'll be able to see your responses, and those of the whole class at EVAF.)

1
Press 1 to signal LEFT
2
Press 2 to signal RIGHT
Graphic - No title - boxonrug

A box sits on a rug on a horizontal frictionless floor. A horizontal force is applied to the right.

In case I it is applied to the rug

In case II it is applied to the box.

In both cases the box and rug accelerate together.

What is the direction of the frictional force that
the rug exerts on the box?

  1. Case I
  2. Case II