Newton's First Law of Motion Sir Isaac Newton was in my mind one of the greatest people who ever lived. He was born in 1642 and died in 1727. He formulated three laws of motion that help explain some very important principles of physics. Some of Newton's laws could only be proved under certain conditions; actual observations and experiments made sure that they are true. Newton's laws tell us how objects move by describing the relationship between force and motion. I am going to try to explain his first law in more simple terms.
Newton's first law of motion states: A body continues in its state of rest or uniform motion unless an unbalanced force acts on it. When a body is at rest or in uniform motion this is called inertia. Let's say that someone parks a car on a flat road and forgets to put the vehicle into park. The car should stay in that spot. This state of being is called inertia. All of a sudden the wind picks up or some kid crashes into the car with a bike.
Both the wind and the kid's bike crashing into the bike are unbalanced forces. The car should start to move. The car might accelerate to two miles per hour. Now we would all assume that the car would come to a stop sometime. We assume this because it is true. It is true because there is friction between the tires and the road.
The car now has inertia in uniform motion. Since there is friction, the car cannot keep moving forever because friction is an unbalanced force acting upon the tires. What if there was not any friction? The car would keep going forever. That is if there was not any wind or a hill or any unbalanced force acting upon the car. This is rather weird just to think about. Because this usually would not happen in our customary world today.
You just would not see a car go on forever. An easy experiment to demonstrate this law is to take a glass jar and put an index or a heavier than paper card over the top of the glass jar. Next, place a coin on the index card. Be sure that the index card is strong enough to support the penny without bending itself. Now place your finger about three centimeters away from the card and flick the card out from underneath the coin.
The coin should fall into the glass jar. The inertia of the coin keeps it in place even when the card is moving underneath it.