1. Welcome to Earth & Physical Science (EPS) Unit 1, Day 4 (T 8/31, W 9/1) Newton’s Second Law (continued) CO 4 and CO 5

2. Bell Starter CB “IN” with Date (8/31) On left page, upper half: Write and answer question using GUESS: Joshua exerts a net force on a puck of mass across an ice rink. Joshua exerts a net force on a puck of mass across an ice rink. Write an equation for the puck’s acceleration (using Newton’s 2 nd Law) (refer to your notes from day 3!) Write an equation for the puck’s acceleration (using Newton’s 2 nd Law) (refer to your notes from day 3!) What is the acceleration if his push is a net force of 5.0 N and the puck’s mass is 0.5 kg? Show work using GUESS. What is the acceleration if his push is a net force of 5.0 N and the puck’s mass is 0.5 kg? Show work using GUESS.

3. Today’s Agenda Applying Newton’s 2 nd Law (CO 4 & CO 5) Check Grades: Student Information Sheets, Missing Work (goals, pretests), and CBs Check Grades: Student Information Sheets, Missing Work (goals, pretests), and CBs WIKI WIKI Warm Up: Algebraic & Newton’s 2 nd Law/GUESS Warm Up: Algebraic & Newton’s 2 nd Law/GUESS Review WB 7—Grade your own in COLOR Review WB 7—Grade your own in COLOR CO 4 and CO 5: Applying Newton’s 2 nd Law CO 4 and CO 5: Applying Newton’s 2 nd Law Continued: Solving Algebraically – GUESS Continued: Solving Algebraically – GUESS Practice/Work Time: “Newton’s 2 nd Law” (WB 9) Practice/Work Time: “Newton’s 2 nd Law” (WB 9) Extension for advanced students, WB10 Extension for advanced students, WB10

4. Welcome Back Please remember to turn off your cell phones and other electronic devices Please remember to turn off your cell phones and other electronic devices Cares, Concerns & Celebrations Cares, Concerns & Celebrations RAPTOR VICTORIES

5. Due Dates Thursday 9/9/10 or Friday 9/10/10: Thursday 9/9/10 or Friday 9/10/10: Unit 1 Assignments Due Unit 1 Assignments Due Monday 9/13/10 or Tuesday 9/14/10: Monday 9/13/10 or Tuesday 9/14/10: Composition Notebook (graded per rubric) Composition Notebook (graded per rubric) Unit 1 Exam (short answer and multiple choice) Unit 1 Exam (short answer and multiple choice)

6. Review: Questions on IV & DV? Questions on IV & DV? Review WB 7-”Force and Acceleration Calculations-- See next slide Review WB 7-”Force and Acceleration Calculations-- See next slide Today’s “IN” (use GUESS format) Today’s “IN” (use GUESS format) Answer: a = 5.0 N/0.5 kg = 10.0 m/s 2 Answer: a = 5.0 N/0.5 kg = 10.0 m/s 2

7. Force and Acceleration Calculations (Homework Due!) ANSWERS 1. F = 6000 N 1. F = 6000 N 2. F = 30 N 2. F = 30 N 3. m = 15 kg 3. m = 15 kg (TRICKY—extra points, needed to know that acceleration of gravity is 9.8 m/s 2 ) (TRICKY—extra points, needed to know that acceleration of gravity is 9.8 m/s 2 ) 4. a = 50 m/s 2 4. a = 50 m/s 2 5. m = 2800 kg 5. m = 2800 kg

8. Write the question here GivensUnknownsEquationSubstitutionSolve (units)

9. CO 3: Mass, Weight, & Inertia (3.3 pp 41-43) Mass: Measure of the amount of matter in an object. Measure of the amount of matter in an object. Mass remains the same on Earth, the moon, or an orbiting space shuttle. Mass remains the same on Earth, the moon, or an orbiting space shuttle.

10. CO 3: Mass, Weight, & Inertia Weight: Weight: Gravitational force an object experiences due to its mass. Gravitational force an object experiences due to its mass. Depends on gravity. Depends on gravity.

11. CO 3: Mass, Weight, & Inertia Inertia: the tendency of an object to remain at rest or in motion with a constant velocity. Inertia: the tendency of an object to remain at rest or in motion with a constant velocity. Example: The baby will remain in the car seat, unless there is a sudden motion and the baby will continue in the direction of the motion (therefore, buckle up for safety). Example: The baby will remain in the car seat, unless there is a sudden motion and the baby will continue in the direction of the motion (therefore, buckle up for safety).

12. CO 3: Mass, Weight, & Inertia Mass is a measure of inertia. Mass is a measure of inertia.

13. CO 4: Newton’s Second Law Newton’s Second LawNewton’s Second Law Use Newton’s 2 nd Law to solve for an unknown variable. Introduction Introduction Introduction (video clip) (video clip)

14. CO 4: Newton’s Second Law Newton’s Second LawNewton’s Second Law Use Newton’s 2 nd Law to solve for an unknown variable. Equation: Equation: acceleration = force/mass acceleration = force/mass Units: Units: Acceleration = m/s 2 Acceleration = m/s 2 Force = N which is kg ● m/s 2 Force = N which is kg ● m/s 2 Mass = kg Mass = kg

15. CO 4 Practice : TB pg 45 #1 & #2 Write the questions and SHOW ALL WORK If you push on a shopping cart, it will accelerate. #1. If you push the same, but the cart is loaded with groceries so it has five times as much mass, what happens to the acceleration? #2. If you push five times harder on the loaded cart, what happens to acceleration?

16. CO 4 Practice : TB pg 45 #1 & #2 Answers If you push on a shopping cart, it will accelerate. #1. Acceleration will be less, only one-fifth as much. #2. It will have the same acceleration as it had without the load.

17. CO 4 Additional Practice Write the questions and SHOW ALL WORK What is the acceleration of a boy on a skateboard (total mass = 58 kg) if the unbalanced forward force on the boy is 15 N? (use GUESS format)

18. CO 5: Acceleration Changes Describe what will happen to acceleration, given a change in one variable (mass or force). Acceleration is indirectly proportional to mass. acceleration ≈ 1/mass Acceleration is indirectly proportional to mass. acceleration ≈ 1/mass Example: Acceleration of unequal masses on air tracks Example: Acceleration of unequal masses on air tracks

19. CO 5: Acceleration Changes Acceleration is inversely proportional to mass. acceleration ≈ 1/mass Acceleration is inversely proportional to mass. acceleration ≈ 1/mass

20. CO 5: Acceleration Changes Acceleration is directly proportional to net force. acceleration ≈ net force Acceleration is directly proportional to net force. acceleration ≈ net force

21. CO 5: Acceleration Changes OUT Practice: Chapter Review pg 52 #10-#11 #10. If the net force acting on a sliding block is tripled, by how much does the acceleration increase? #11. If the mass of a sliding block is tripled at the same time the net force is tripled, how does the resulting acceleration compare to the original acceleration?

22. CO 5: Acceleration Changes Answers: Chapter Review pg 52 #10-#11 #10. Acceleration also triples. #11. If you triple the force acting on three times the mass, there’s no change in acceleration. Acceleration remains the same.

23. CO 4 & CO 5: Note Acceleration: is a change in velocity divided by the time interval in which the change occurred. Acceleration: is a change in velocity divided by the time interval in which the change occurred. Acceleration = Acceleration =

24. CO 4 & CO 5: Practice Show all your work!! Show all your work!! Use GUESS format (or no credit) Use GUESS format (or no credit) Work individually and with your learning goals in mind Work individually and with your learning goals in mind Newton’s 2 nd Law Problem Set(WB9) Newton’s 2 nd Law Problem Set(WB9) Homework if you don’t finish! Homework if you don’t finish! “Newton’s 2 nd Law Problem Set (Extension)” Worksheet (WB10) – if you have time “Newton’s 2 nd Law Problem Set (Extension)” Worksheet (WB10) – if you have time

25. What’s Due Next Time? Complete: Complete: Newton’s 2 nd Law Problem Set (WB7) Newton’s 2 nd Law Problem Set (WB7)