What is a Force? Force Newton Net force Chapter 1, Section 2 (pages 10-13) Vocabulary: Force Newton Net force

A push or pull! Force p. 10

Scientists use the unit called “Newton (N)” to express Newton p. 10 Scientists use the unit called “Newton (N)” to express Force!

List 5 ways you have exerted Force today? 1. Pushing the alarm clock button off. 2. Pushing the shower switch on and off this morning. 9. Pulling your locker open. 10. Pushing your locker shut! 3. Pushing the soap on yourself or the washcloth. 11. Pushing another person (stop doing that!) 4. Pushing or pulling your toothbrush. 12. Pushing or pulling a chair 5. Pushing or pulling a comb or brush. 13. Sitting (pushing) on your seat 6. Pulling your covers up to make your bed 14. Pushing or pulling your note sheet. 7. Pulling your book bag up on to your shoulder. 15. Pulling your pencil/pen 8. Pulling your books out of the bag 16. Pushing your pencil or pen

The Earth and Moon exert an unseen force (gravity) on There are unseen sources and receivers of force as well Gravity The Earth and Moon exert an unseen force (gravity) on each other. p. 11

unseen force is magnetism Another Example of an unseen force is magnetism

The Earth has Magnetic fields as well

The combination of all the forces Net force The combination of all the forces acting upon an object p. 11

Just add them together and include the direction. Figure out the total net force when force is applied in the same direction Just add them together and include the direction. 30 N 35 N Answer: 65 N to the left

Forces in Different Directions p. 12

forces are equal (balanced) Balanced Force p. 12 When the forces on an object produce a net force of 0 N, the forces are equal (balanced)

Balanced Force Here’s another example of A balanced force. Use this illustration to explain the term “balanced force.”

Unbalanced Force p. 13 When the net force is not 0 N. Produces a change in motion Necessary to cause a non moving object to start moving 4. Necessary to change the motion of the moving object

Unbalanced forces Produce a change in motion Unbalanced forces are necessary to cause a non moving object to start moving When the net force is not 0 N. Unbalanced forces are necessary to change the motion of the moving object

Contact vs. Non-Contact Forces Contact forces: There's a contact between two objects, two people or a person and an object. Contact Forces Frictional Force Tension Force Normal Force Air Resistance Force Applied Force Spring Force

NON-Contact Forces Action-at-a-Distance Forces Non-contact force: no contact takes place Action-at-a-Distance Forces Gravitational Force Electrical Force Magnetic Force

An object at rest will remain At rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This law is called “the Law of Inertia.” Newton’s first Law of Motion.