Newton’s Laws Sir Isaac Newton was an English physicist and mathematician in the late 1600’s and early 1700’s. He is well known for ‘discovering’ gravity and his three laws of motion.
Newton’s First Law Newton’s first law states that an object at rest will remain at rest, and an object in motion will remain in motion, until acted upon by an outside force.
Newton’s First Law Lets say you have a ball. The ball is sitting still on the ground, and you kick it. The ball begins to roll and bounce in the direction you kicked it because it is being acted upon by an outside force. What is the outside force? Your foot kicking the ball is the outside force. The ball was at rest, and when you kicked it, it was in motion.
Newton’s First Law That ball is going to remain in motion until it is acted upon by another outside force. The ball hits the fence in your backyard and stops, because a force is being acted upon it. What is the outside force? The outside force is the fence. The ball is going to hit the fence, thus causing it to stop. If there were no fence or other outside force to stop it, such as friction, gravity or air resistance, the ball would keep going and going for ever.
Newton’s Second Law Newton’s second law states that the greater the force, the greater the acceleration.
Newton’s Second Law You and a friend are racing on skateboards. The harder you push, the faster you go. Why is this? The harder you push off the ground with your foot, the more force you are applying, therefore, increasing your speed.
Newton’s Third Law Newton’s Third Law states that for every action there is an opposite and equal reaction.
Newton’s Third Law Jumping rope is one example of Newton’s third law. Why is that? When you jump, you exert a force on the ground, and the ground exerts a force on you, causing you to move upward.
Inertia The tendency of an object to maintain its state of rest or uniform motion unless acted upon by an external force.