1. Newton’s Second and Third Laws
Ch. 4 Section 3

2. Newton’s 2nd Law
The acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to the object’s mass.
In other words…
Fnet= mass x acceleration

3. Example
Roberto and Laura are studying across from each other at a wide table. Laura slides a 2.2 kg book toward Roberto. If the net force acting on the book is 1.6 N to the right, what is the book’s acceleration?
Use Newton’s 2nd Law to solve!

4. Newton’s 3rd Law
If two objects interact, the magnitude of the force exerted on object 1 by object 2 is equal to the magnitude of the force simultaneously exerted on object 2 by object 1, and these two forces are opposite in directions.
In other words…
For every action, there is an equal and opposite reaction.

5. Action and Reaction Forces
Action force= force that object 1 exerts on object 2
Reaction force= force that object 2 exerts back on object 1
*Action force is equal and opposite in reaction to the reaction force.
*Reaction forces happen at the SAME TIME as action forces.

6. p. 133
Action/ reaction forces on hammering a nail into wood…read!

7. Examples

12. Newton’s 2nd Law Practice