Yes. On a circular path, the direction of motion is constantly changing. Change of direction is acceleration, even at constant speed.
Answer:
If you push horizontally with a small force, static friction establishes an equal and opposite force that keeps the book at rest. As you push harder, the static friction force increases to match the force. Eventually maximum static friction force is exceeded and the book moves.
Explanation:
I think the answer is 4) All of the above!! :)
