Ahorse pulls forward on a carriage with a given force. by newton's third law, the carriage must be pulling on the horse backward with an equal and opposite force. given this, what explains why the horse and carriage can move forward? two brown horses pulling wooden carriage image from wikimedia commons, cc by-sa 2.0 choose 1 choose 1 a the cart is rolling on wheels while the horse's hooves have traction with the ground b the forward force of the horse is just big enough to overcome the backward force of the cart and start the cart forward c the cart's force is only in reaction to the horse's force so it does not define direction of movement d there is a brief moment where the horse pulls before the reaction force kicks in e the forward and backward forces are equal, so it actually can't move forward