Nucleic acids, proteins, and other large biological molecules are known as polymers because

image result for what happens whenever a net force acts on an object

if an object has a net force acting on it, it will accelerate. the object will speed up, slow down or change direction. an unbalanced force (net force) acting on an object changes its speed and/or direction of motion. an unbalanced force is an unopposed force that causes a change in motion.