Newtons law of motion
- 1. Newton’s Laws of Motion
- 3. Newton’s Laws of Motion Review
- 4. Background Sir Isaac Newton (1643-1727) an English scientist and mathematician famous for his discovery of the law of gravity also discovered the three laws of motion. He published them in his book Philosophiae Naturalis Principia Mathematica (mathematic principles of natural philosophy) in 1687. Today these laws are known as Newton’s Laws of Motion and describe the motion of all objects on the scale we experience in our everyday lives.
- 5. “If I have ever made any valuable discoveries, it has been owing more to patient attention, than to any other talent.” -Sir Isaac Newton
- 6. Newton’s First Law An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an unbalanced force.
- 7. What does this mean? Basically, an object will “keep doing what it was doing” unless acted on by an unbalanced force. If the object was sitting still, it will remain stationary. If it was moving at a constant velocity, it will keep moving. It takes force to change the motion of an object.
- 8. What is meant by unbalanced force? If the forces on an object are equal and opposite, they are said to be balanced, and the object experiences no change in motion. If they are not equal and opposite, then the forces are unbalanced and the motion of the object changes.
- 9. Some Examples from Real Life Two teams are playing tug of war. They are both exerting equal force on the rope in opposite directions. This balanced force results in no change of motion. A soccer ball is sitting at rest. It takes an unbalanced force of a kick to change its motion.
- 10. Newton’s First Law is also called the Law of Inertia Inertia: the tendency of an object to resist changes in its state of motion The First Law states that all objects have inertia. The more mass an object has, the more inertia it has (and the harder it is to change its motion).
- 11. Newton’s Second Law Force equals mass times acceleration. F = ma Acceleration: a measurement of how quickly an object is changing speed.
- 12. What does F = ma mean? Force is directly proportional to mass and acceleration. Imagine a ball of a certain mass moving at a certain acceleration. This ball has a certain force. Now imagine we make the ball twice as big (double the mass) but keep the acceleration constant. F = ma says that this new ball has twice the force of the old ball.
- 13. More about F = ma If you double the mass, you double the force. If you double the acceleration, you double the force. What if you double the mass and the acceleration? (2m)(2a) = 4F Doubling the mass and the acceleration quadruples the force.
- 14. Newton’s Third Law For every action there is an equal and opposite reaction.
- 15. • Explanation: • It means that whenever there is two interacting bodies then there is a pair of forces acting on bodies ,the size of force acting on one body is equal to the size of force acting on the other body.
- 16. • Example 1 • When a person is walking .person is exerting force on the ground and at the same time ground is exerting same size force on the person but in opposite direction.
- 17. Example 2 A boat is at rest in the canal. Throwing a package from the boat to the shore then the boat will move out ward. This is also a example of third law
- 18. Review Newton’s First Law: Objects in motion tend to stay in motion and objects at rest tend to stay at rest unless acted upon by an unbalanced force. Newton’s Second Law: Force equals mass times acceleration (F = ma). Newton’s Third Law: For every action there is an equal and opposite reaction.
- 19. THE END