1. 4.3 Newton’s Second Law of Motion

2. 4.3 Newton’s Second Law of Motion
Force is proportional to mass and acceleration.
The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the object’s mass.
The direction of the acceleration is in the same direction as the applied force

3. 4.3 Newton’s Second Law of Motion
Formula:
F = ma

4. Roberto and Laura are studying across from each other at a wide table
Roberto and Laura are studying across from each other at a wide table. Laura slides a 2.2 kg book towards Roberto. If the net external force acting on the book is 2.6 N to the right, what is the book’s acceleration?

5. Newton’s Third Law of Motion

6. Newton’s Third Law of Motion
For every action there is an equal and opposite reaction
Force always exist in pairs
Pairs are known as action-reaction pairs
Field forces also exist as pairs

7. Identify the action-reaction pair in the following situations.
A person takes a step
A snowball hits someone in the back

8. Identify the action-reaction pair in the following situations.
A baseball player catches a ball
A gust of wind strikes a window

9. The forces acting on a sailboat are 390 N north and 180 N east
The forces acting on a sailboat are 390 N north and 180 N east. If the boat has a mass of 270 kg, what are the magnitude and direction of its acceleration?