If Newton's 3rd law is true (all actions have an equal and opposite reaction), then how can any object move?

(Using diagrams to aid explention)This is a common difficulty students with Newton's third law, because in isolation it makes sense; If i am pushing a cart, and the cart imparts an equal amount of force on me than i push on it, then surely nothing must move?The solution to this is that each force is balanced, but not overall force. So for the cart example, yes, i am being pushed back with a force equal to the force i impart on the cart. However, when i am accelerating, the total forces on my body are not balanced - my feet are pushing on the earth with a frictional force greater than the force the cart is pushing backwards on me, therefore there is an overall resultant force forwards pushing the cart. The trick on how to spot this when answering a question is to pay attention to what forces are acting on which specific bodies - In this case the cart and me. Also note that this is a great way to reaffirm understanding of the first law - when all forces are balanced (no net force), a body will remain at rest or moving with a constant velocity. Therefore when i stop accelerating, and the forces become balanced, then i will be moving at a constant velocity.