1. Vector Nature of Newtons 2 nd Law of Motion and Newtons 3 rd Law 4.4 and 4.5

2. 4.4 Vector Nature of Newtons 2 nd Law of Motion Vectors – F, a, v Use components – x and y Rewrite 2 nd law – F x = ma x – F y = ma y

3. Example 1 An 10,000-kg airplane is pointing north and applying 3,000 N of thrust. The wind is blowing west and applying a 1,500-N force on the plane. Ignoring air-resistance, was is the magnitude of the x and y components of the resultant acceleration? a x = -6.67 m/s 2 a y = 3.33 m/s 2

4. Example 2 If the airplane in the previous problem was traveling 200 m/s due north when the wind started blowing, what was its displacement after 1 minute? x = -12000 m y = 18000 m

5. 4.5 Newtons 3 rd Law of Motion You have a car crash Other car hits you, so your car crunched Why other car crunched too?

6. Newtons 3 rd Law of Motion Whenever one body exerts a force on a second body, the second body exerts an equal and opposite force. Every action has equal and opposite reaction

7. Acceleration due to the 3 rd Law A 70-kg diver jumps off a boat on a smooth lake. He applies 75 N horizontally against the 500-kg boat. What are the accelerations of the diver and the boat? a d = 1.07 m/s 2 a b = -0.15 m/s 2

8. Practice Work Try 115 #CQ6 – 8, P10 – 14, 16 Total of 9 problems