1. Forces

2. Rate Yourself 4 = Explain real world situations using academic voc. and Newton’s laws. 3 = Investigate and describe types of forces. Differentiate between mass and weight. 2 = Describe the relationship between distance, mass, and gravitational force. 1 =Identify types of forces.

3. What is a Force? A force is a push or a pull. A force is described by its strength and by the direction in which it acts. The strength of a force is measured in the SI unit newton (N) and an arrow represents the direction of the force.

4. Contact vs. Noncontact Forces Contact Force: A push or a pull on one object by another that is touching it. Noncontact Force: A force that one object can apply to another object without touching it.

5. Combining Forces Net force = a combination of all forces acting on an object. Same direction = add Opposite direction = subtract

6. Think Pair Share If Sandy peddles her bike with a force of 20 N to the east and the wind pushes back with a force of 5 N, what is the net force?

7. Think Pair Share Jamey pushes the door with a force of 9 N. His little brother pushes in the same direction with a force of 7 N. The door pushes back with a force of 15 N. Will the door open? Explain.

8. Unbalanced Forces can cause an object to start moving, stop moving, or change direction. 10 N 5 N Balanced Forces are equal forces acting on one object from opposite directions.

9. Other Types of Forces

10. Think Pair Share What would our world be like without forces?

11. Rate Yourself 4 = Explain real world situations using academic voc. and Newton’s laws. 3 = Investigate and describe types of forces. Differentiate between mass and weight. 2 = Describe the relationship between distance, mass, and gravitational force. 1 =Identify types of forces.