When you push downward on a book at rest on a table, you feel an upward force. Does this force depend on friction? Defend your answer.
It depends on the angle that you push with. There is no friction involved if you push straight down at a 90 degree angle. Any other angle will involve friction which, if exceeded, will cause the book to move. Yes. when push the book the book exerts normal force on hand and the hand also exerts force on book and the force from the table holding it up balances out the force from gravity pulling it downward. At rest , the book actually has two forces acting Weight of the book acting towards downward and the normal force exerted by the table on the book and the direction is upwards