1. Newton’s Laws of Motion

2. In this PPT BLACK text should be recorded in your physics notebook Purple text does not need to be recorded, or may be on your Notes Supplement worksheet I will let you know when it is time to refer to your Notes Supplement sheet

3. Some Vocabulary… Weight – how strong gravity is pulling on you Gravity – a pull towards the center of an object  On Earth, the pull on an object towards the center of the Earth  The more mass an object has, the stronger the pull of gravity. The Earth has a gravitational pull 6 times greater than that of the moon Jupiter has a gravitational pull 2.4 times greater than that of Earth

4. Gravity and Weight Mr. Albano’s weight on Earth is ~60kg. What is his weight on the moon? What is his weight on Jupiter? Does his mass change on the moon? On Jupiter?

5. Newton’s First Law of Motion An object in motion stays in motion unless acted on by an unbalanced force An object at rest (not moving) will stay at rest unless acted on by an unbalanced force

6. Newton’s First Law of Motion Also known as the Law of Inertia  Inertia – The reason an object stays at rest, or in motion

7. Newtons’s 1 st Law and You Don’t let this be you. Wear seat belts. Because of inertia, objects (including you) resist changes in their motion. When the car going 80 km/hr is stopped by the brick wall, your body keeps moving at 80 km/hr.

8. Newton’s First Law “Rounding” Corners  Can you run around the desk without slowing down? “Rounding” Bases

9. Another Inertia Example I’m safe over here. That guy is toast! Stay over there, you’ll be safe!

10. Hehehe

11. More Inertia “Red Light / Green Light”

12. “Weightlessness” Without friction, Newton’s 1 st Law is perfect  Example – Outer Space How a shuttle orbits  Weightless = Falling???

13. GRAVITY Forward Inertia

15. Parabolic Flight (Projectile Motion)

16. Projectile Motion Projectile - object thrown or launched and does not move under its own power The combination of initial forward velocity and the downward force of gravity causes things to travel in a curved path (parabola)  Ex: throwing a ball, a ski jump, a cannon ball being shot, punting a footballpunting a football If it wasn’t for gravity, the ball would continue to travel in a straight line due to Inertia

17. Videos 1 st Law – NFL 1 st Law – NFL 2 nd Law - NFL 2 nd Law - NFL 3 rd Law - NFL 3 rd Law - NFL

18. Newton’s 2 nd Law of Motion

19. Newton’s 2 nd Law Force = mass x acceleration Acceleration = The rate something speeds up, or slows down

20. Force – let’s review! How hard something is pushing or pulling Measured in “Newtons” (N) Ex. I pushed the ball up the hill with 10 N of force

21. Units for 2 nd Law Problems For our purposes, we will only be using the following units (standard SI units) when solving Newton’s 2 nd Law related problems:  FORCE = Newtons (N)  MASS = kilograms (kg)  ACCELERATION = m/s/s (meters per second per second)

22. F = m x a What happens to the force if:  You increase the acceleration?  You increase the mass?

23. Examples Two students are in a baseball game. The first student hits a ball very hard and it has a greater acceleration than the second student who bunts the ball lightly. A soccer ball accelerates more than a bowling ball when thrown with the same force.

24. Example 1 – Prove it mathematically! Two students are in a baseball game. The first student hits a ball very hard and it has a greater acceleration than the second student who bunts the ball lightly. Baseball has a mass of 0.15kg. Student A hits very hard with a Force of 1000N Student B bunts with a Force of 100N a = F ÷ m Student A  a = 1000 ÷ 0.15 = 6666.67 m/s/s Student B  a = 100 ÷ 0.15 = 666.67 m/s/s

25. Example 2 – Prove it mathematically! A soccer ball accelerates more than a bowling ball when thrown with the same force. Soccer ball mass = 0.5kg Bowling ball mass = 6.5kg Force = 50N Soccer ball  a = 50 ÷ 0.5 = 100 m/s/s Bowling ball  a = 50 ÷ 6.5 = 7.7 m/s/s

26. Newton’s 2 nd Law proves that different masses accelerate to the earth at the same rate, but with different forces. Objects that are falling accelerate to the ground at the same rate (9.8 m/s/s)  When the upward force of air resistance = the downward force of gravity pulling on the object, it stops accelerating. We call this Terminal Velocity However, because of the 2 nd Law we know that they don’t hit the ground with the same force. Objects that are falling accelerate to the ground at the same rate (9.8 m/s/s)  When the upward force of air resistance = the downward force of gravity pulling on the object, it stops accelerating. We call this Terminal Velocity However, because of the 2 nd Law we know that they don’t hit the ground with the same force. F = ma 98 N = 10 kg x 9.8 m/s/s F = ma 9.8 N = 1 kg x 9.8 m/s/s

27. Can a cat survive a fall from a planeCan a cat survive a fall from a plane? There’s another reason besides a cat’s natural instincts to detect acceleration… Cat’s average mass = 9 kg Human’s average mass = 75 kg Acceleration due to gravity = 9.8 m/s/s Who hits the ground with more FORCE?

28. Example: A boulder has a mass of 8 kg, and you push it so that it accelerates 3 m/s/s. How much force did you push it with?

29. Example: You push your friend in the next desk with a force of 18 Newtons. They have a mass of 2 kg. How much will they accelerate?

30. Example: Your parents ask you to help the neighbors move. They ask you to pull a box into the truck. You pull with exactly 35 Newtons of force, and the box accelerates 5 m/s/s. What was the mass of the box?

31. Newton’s 3 rd Law of Motion

32. Newton’s 3 rd Law Every action has an equal and opposite reaction Example:  Action = You kick a soccer ball  Reaction = The soccer ball kicks you!

33. In other words… “This means that for every force there is a reaction force that is equal in size, but opposite in direction. That is to say that whenever an object pushes another object it gets pushed back in the opposite direction equally hard.”

34. Examples  Fish through water - water goes back, fish goes forward  Bird flying - wings push down, air pushes up  Fire hose - water comes out, hose pushes back

35. Balloon

36. Rocket Example The rocket's action is to push down on the ground with the force of its powerful engines, and the reaction is that the ground pushes the rocket upwards with an equal force.

37. Gravity Example

38. More Examples Space shuttle lifting off Airplane flying through the air EVERY force has a reaction force