Warm Up 4/18/12

1. Warm Up 4/18/12 Calculate the speed for the following problems: • If you walk to Northlake from JMMS it takes you 2 hours. If Northlake is 24 miles away, how fast could you get to the mall? • Ms. Adeeyo drove from Durham to Charlotte after her aunts funeral. If she drove 110 miles for 2 hours how fast was she going?

2. Announcements • Test on Friday! • I will show you your grades tomorrow. • Are you ready for the EOG’s? • This year, your End of the Year assessment in science is the 8th grade science EOG (I will take off questions you have not learned yet). • What happens if you pass? You will take honors science class next year 

3. Think and Write 10 minutes • Ms. Adeeyo will show you several documents that are very important to her. • Will your teachers write good recommendation letters for you one day? • Why or why not? • What can you do now to prepare yourself for the future?

4. Velocity and Acceleration Speed it up!

5. What is velocity? • Velocity is a speed in a specific direction. • Velocity gives both the speed and direction of the object’s motion. • You should have this in your notes. If you don’t or cant remember, write it down.

6. Acceleration • Acceleration is a change in velocity

7. Check for Understanding What two components make up velocity?

8. Check for Understanding Velocity Speed Direction

9. Acceleration • Def.: Change in _________ • Can be change in speed or direction • (speed up, slow down, or change direction)

10. Check for Understanding Is this ball accelerating? Yes! Because the direction is changing.

11. Which cars are accelerating? A B C Cars B and C!

12. Acceleration Acceleration is not just a change in velocity, it’s how fast that change happens.

13. Which car has the greatest acceleration? A B C Car C!

14. Acceleration To measure it, you must know the initial velocity, the final velocity, and the time it takes to make the change.

15. Acceleration • Def.: Change in velocity • Can be change in speed or direction • (speed up, slow down, or change direction) • Acceleration = ∆v/ t

16. Acceleration • Initial Velocity –Object’s velocity when you start measuring acceleration. • Final Velocity –Object’s velocity when you finish measuring acceleration. •  - Greek letter delta – “change”

17. Acceleration The unit for acceleration is m/s2. Acceleration = change in velocity time  v a = t

18. Acceleration v is the difference between the final velocity (vf) and the initial velocity (vi). v = vf- vi

19. Acceleration • Def.: Change in velocity • Can be change in speed or direction • (speed up, slow down, or change direction) • Acceleration = ∆v/ t • ∆v = vf – vi

20. Example 1 • A roller coaster’s velocity at the top of a hill is 10m/s. Two seconds later it reaches the bottom of the hill with a velocity of 26m/s. What is the acceleration of the roller coaster?

21. Answer • vf = 26 m/s vi = 10 m/s t = 2 s • Acceleration = ∆v/ t • a = 26m/s – 10m/s 2 s a = 16m/s 2s a = 8m/s/s or 8m/s2

22. Examples 2-4 – Try them! 2. A car travels at 60 miles per hour around a curve. Is the car accelerating? 3. A car travels in a straight line at 60 mi/hr. Is the car accelerating? 4. A car goes from 0 mph to 60 mph in 6 seconds. What’s the car’s acceleration?

23. Answers: 1. Yes! Because it’s changing direction. 2. No! It’s not changing speed or direction. 3. -vf = 60 mph vi = 0 mph t = 6 s -a = vf – vi t -a = 60 – 0 mph = 10 m/s2 6 s

24. Graphing Velocity vs. Time Constant acc. No acc. Increasing acc.

25. I think we’ve seen this before… Constant speed No motion Increasing Speed

26. Warm Up 4/19/12 1. Why do you think a penguin slides/rolls further than a bear?

27. Announcements • Test tomorrow!

28. Sir Isaac Newton • Born on December 25th, 1642 and died March 20th, 1727. • Considered to be one (if not the) greatest and most influential scientist who ever lived.

29. What’s so great about him? • Wrote a book about classical mechanics. • Described universal gravitation • Three laws of motion.

30. Why’s he important to us as 7th graders? • We are studying motion currently and are beginning to learn about his three laws.

31. Newton’s Laws • Newton’s Laws are all about force and motion.

32. Newton’s 1st Law • Newton’s 1st Law: An object at rest will remain at rest and an object in motion will remain in motion unless an unbalanced force acts upon it.

33. Newton’s 1st Law • Anytime you read about a situation where something is at rest and then it starts moving or is moving and then it stops, it is talking about Newton’s 1st Law.

34. Newton’s 1st Law • There is a box that is sitting on the floor at rest. It will remain at rest until somebody pushes it. At rest… In motion…

35. Newton’s 1st Law • You are driving in a car with no seat belt on. You see a family of ducks and slam on your brakes to avoid hitting them. Since you are not wearing your seat belt, you fly out of the car (remain in motion) until you hit the ground (an unbalanced force). AHH! Ouch In motion… At rest…

36. Warm Up 4/20/12 • What is the formula for speed? • What is the formula for acceleration? • How are the two different from each other?

37. Announcements • Have a great weekend 

38. Test review (this looks very similar to your test) 1. Meg and Emi left JMMS at the same time. Meg lives further away from the school than Emi, but they arrive at their houses at the same time. Compare their speeds. 2. Jaime and Clara are racing. Jaime runs 40 meters in 8 seconds. Clara travels 80 meters 20 seconds. Which runner is the fastest? Show your complete work using the speed triangle and label correctly! 3. Tennessee Titans player, Chris Johnson takes 4.24 seconds to run a 40 meter dash. What is his speed? Show your work on the speed triangle and label.

39. More review • Describe the acceleration as positive, negative, or zero.

40. Anymore questions? • Speak now or forever hold your peace?

41. Testing time • Clear everything off your desk! • Get out a sheet of notebook paper. • DO NOT WRITE ON TEST SHEETS (Class set) • Good luck 

42. Warm Up 4/23/12 • Describe the difference between speed and acceleration? • Why is it important for us to have final and intial velocities when calculating acceleration? • Who is Sir Isaac Newton? What did he discover that was so important to science?

43. Announcements • Ms. Adeeyo’s birthday is tomorrow  • Please be sure that you are completing all homework assignments (I will place zero’s for students that do not turn their assignments in)

44. Sir Isaac Newton • Born on December 25th, 1642 and died March 20th, 1727. • Considered to be one (if not the) greatest and most influential scientist who ever lived.

45. What’s so great about him? • Wrote a book about classical mechanics. • Described universal gravitation • Three laws of motion.

46. Why’s he important to us as 7th graders? • We are studying motion currently and are beginning to learn about his three laws. • Newton’s Laws are all about force and motion.

47. Newton’s 1st Law • Newton’s 1st Law: An object at rest will remain at rest and an object in motion will remain in motion unless an unbalanced force acts upon it.

48. Newton’s 1st Law • Anytime you read about a situation where something is at rest and then it starts moving or is moving and then it stops, it is talking about Newton’s 1st Law.

49. Newton’s 1st Law • There is a box that is sitting on the floor at rest. It will remain at rest until somebody pushes it. At rest… In motion…

50. Newton’s 1st Law • You are driving in a car with no seat belt on. You see a family of ducks and slam on your brakes to avoid hitting them. Since you are not wearing your seat belt, you fly out of the car (remain in motion) until you hit the ground (an unbalanced force). AHH! Ouch In motion… At rest…