Another Action/Reaction question...Donkey and a cart!!! Hey, i am doing this for prety much basic physics but i need to: Draw all the action-reaction pairs. If the cart pulls on the mule with the same force that the mule pulls on the cart, how can the mule move? Can you help me out?!?! Thanks John The mule would pull it if it exerted more force than the cart puts onto the mule, Right? Also, are there only F1 and -F1, or are there gravity forces that act as action reaction forces?