What are the action and reaction forces at work in this picture?
a
the flower vase is pushing up and gravity is pulling down
b
the book is pushing on the table and the table is pushing on the book
c
gravity is pulling the book downward
d
friction is pushing up and gravity is pulling down
Without a picture, I can't refer to the specific elements within it. However, I can explain the forces generally in such a common scenario. Assuming there is a flower vase on a table and a book on the same table, the forces at work, in general, would be:
a) The flower vase is pushing down on the table due to gravity, and the table is exerting an equal and opposite force upward on the vase (action and reaction force pair according to Newton's Third Law). The vase is also being pulled down by gravity.
b) The book is also pushing down on the table due to gravity, and the table is exerting an equal and opposite force upward on the book (another pair of action and reaction forces).
c) Gravity is indeed pulling the book downward, which is the force due to the mass of the book and the acceleration caused by Earth's gravity.
d) If there is no motion and no sliding occurring, friction would not be considered an 'upward' force here. Friction typically opposes motion, so if the book were sliding along the table, kinetic friction would be acting in the opposite direction to the motion. If the book is stationary, static friction could be in effect if there were some lateral force trying to move the book, but in the absence of lateral motion, static friction would not be considered to be acting in the "up" direction.
In the context of a stationary setting with a book and vase on a table, the most pertinent forces would be the force of gravity pulling down on these objects and the normal force of the table pushing up on them, constituting action-reaction force pairs. So both a) and b) are correct regarding the forces at work on the vase and the book, respectively. c) is also correct but is only mentioning the force of gravity on the book, not the reaction force from the table. Option d) does not accurately describe the scenario unless motion is involved.