I have a question for which I am intensely confused. Lets say a car was pushing a big truck from behind. And the car (and truck) are accelerating, then there is a breakdown because the car applies all the force it has to the truck, which pushes back with equal force. So the car shouldn't be moving. Only the truck would experience a little acceleration. For example, using completely unrealistic numbers. Looking just at the truck, it has the force of gravity (unimportant), a force pushing forward (500N), and the force of friction (200N). Then the car must have a force of 500N forward, a force of 500N pushing backward due to the truck, and no force of friction. Think about a car hitting a wall. So in theory, if this situation occurs irl, then the car and truck would be playing ping pong. The truck moves forward a little, then the car moves forward (because no backward force anymore) hits the truck and stops (because it is applying force on the truck which is pushing back again), then the truck moves forward and so on. Of course, this could be happening in infinitely small time intervals so it LOOKS like the car never breaks contact. So can someone explain if my reasoning is correct or flawed?