Use Newton's third law of motion to explain why it's easier to turn a

truck when it is empty than when it is carrying a heavy load.

People have probably always observed objects in motion and have madeobjects move around. For many centuries, scientists thought they kneweverything about this. However, the Italian scientist Galileo Galilei, wholived from 1564 to 1642, began to think about motion in a new way. Isaac Newton, who was born the year Galileo died, built upon his dis-coveries and developed three laws. Newton's laws were revolutionary, asthey seemed to go against everyday experience and observation. Today, parts of Newton's three laws are still the basis for understanding motion. Newton's First Law: The Law of InertiaNewton's first law, also known as the Law of Inertia, can be difficult tofully understand. It describes an object's resistance to changing itsmotion and its tendency to keep doing whatever it is doing. A changein motion can be a change in an object's speed, direction, or both. Forexample, a car that speeds up to pass another car, or that turns a cor-ner is changing its motion. Newton's first law states that an object'smotion cannot change unless a force acts on the object. In otherwords, it takes a force to overcome an object's inertia and to make theobject go faster, slower, or change direction.