2. Who was Sir Isaac Newton? Born in England, Isaac Newton was a highly influential physicist, astronomer, mathematician, philosopher, alchemist and theologian. In 1687, Newton published Philosophae Naturalis Principia Mathematica, what is widely regarded to be one of the important books in the history of science. In it he describes universal gravitation and the three laws of motion, concepts that remained at the forefront of science for centuries after.

3. Newton’s law of universal gravitation describes the gravitational attraction between bodies with mass, the earth and moon for example. Newton’s three laws of motion relate the forces acting on a body to its motion. The first is the law of inertia, it states that ‘every object in motion will stay in motion until acted upon by an outside force’. The second is commonly stated as ‘force equals mass times acceleration’, or F = ma. The third and final law is commonly known as ‘for every action there is an equal and opposite reaction’. Who was Sir Isaac Newton?

4. Newton ’ s First Law of Motion

5. First we need to define the word FORCE: The cause of motion (what causes objects to move) Two types of forces –Pushes –Pulls Slide from www.science-class.netwww.science-class.net

6. Forces may be balanced or unbalanced Balanced forces – all forces acting on an object are equal –There is NO MOTION Unbalanced forces – one or more forces acting on an object are stronger than others –There is MOTION A NET FORCE

7. Objects at Rest Objects at rest tend to stay at rest unless acted upon by a outside force. [push or pull] Newton described this tendency as inertia. Inertia can be described as the tendency of an object to keep doing whatever it’s doing.

8. Mass & Inertia Mass is the amount of matter in an object. The more MASS an object has, the more INERTIA the object has. Bigger objects are harder to start & stop Which vehicle has more inertia? Slide from www.science-class.netwww.science-class.net

9. What about objects that are already in motion? Newton stated that objects in motion tend to stay in motion until acted upon by a outside force (or hits it.)

10. Newton ’ s 1 st Law (also known as the Law of Inertia) A moving object moves in a straight line with constant speed unless a force acts on it. The tendency of an object at rest to remain at rest and an object in motion to remain in motion unless acted upon by an unbalanced force. Objects do not change their motion unless a force acts on them

11. Newton’s 1 st Law Examples car suddenly stops and you strain against the seat belt when riding a horse, the horse suddenly stops and you fly over its head the magician pulls the tablecloth out from under a table full of dishes the difficulty of pushing a dead car car turns left and you appear to slide to the right

12. 1. 3. 2.

13. Newton ’ s Second Law of Motion How fast does it go?

14. Acceleration An unbalanced force causes something to accelerate. It is the measure of how quickly the velocity of an object changes.

15. Acceleration Acceleration is directly related to the size of the force and the direction of the force. It accelerates in the direction YOU push or pull it.

16. In other words…. Large Force = Large Acceleration F a

17. In other words…. Small Force = Small Acceleration F a So….if you push twice as hard, it accelerates twice as much.

18. But there is a twist…. Acceleration is INVERSELY related to the mass of the object.

19. In other words…..using the same amount of force…. F Large Mass a Small acceleration F Small Mass Large acceleration a

20. Newton ’ s Second Law Newton, that brilliant genius, observed those “ rules ” of acceleration and came up with his second law of motion. It is both a formula & a law.

21. Newton ’ s Second Law The greater the force applied to an object, the more the object will accelerate. It takes more force to accelerate an object with a lot of mass than to accelerate something with very little mass. F = ma Force = Mass x Acceleration

22. hitting a baseball, the harder the hit, the faster the ball goes accelerating or decelerating a car The positioning of football players - massive players on the line with lighter (faster to accelerate) players in the backfield a loaded versus an unloaded truck

23. Practice Question Ms. Nail pushes a buggy with a constant force through the isle at Home Depot. She then attaches another cart to the first on and continues to push with the same amount of force, but she notices that the carts move more slowly. Explain why. Answer: Acceleration of an object is proportional to the amount of force applied to the object and the mass of the object.

24. third law : For every action force, there is an equal and opposite reaction force. (Forces are always paired)

25. Examples of Newton’s 3 rd Law a)rockets leaving earth b)guns being fired c) Diving from a boat in the middle of a lake and you go forward and the boat goes backwards d) Pushing against each other and accelerating apart. e) jumping out of a boat onto the dock f) Using a paddle to push the water backwards, moves the kayak forward

26. Label on your paper

28. Examples of Newton’s 3 rd Law Newton’s third law: "For every action, there is an equal and opposite reaction." When you fire a gun you feel the recoil. Some of the funniest things in cartoons follow physics that have been exaggerated or just plain ignored. Wyle Coyote hangs suspended in space over that canyon for a lot longer than an object would in reality, but it is the anticipation of the drop and Wyle's facial recognition of the upcoming pain that is so classically cartooney. So some laws are stretched for comical effect.

29. Examples of Newton’s 3 rd Law