3. First Law : An object at rest stays at rest. An object in motion, stays in motion, unless acted upon by an unbalanced force.

4. 1 st Law Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

5. 1 st Law Once airborne, unless acted on by an unbalanced force (gravity and air – fluid friction), it would never stop!

6. Also called: law of inertia seat belt law or lazy law

7. Inertia A property of matter The tendency of an object to resist any change in its motion The greater the mass the greater the inertia The greater the speed the greater the inertia

8. FORCE = Any push or pull which causes something to move. What is a Force?

9. Examples of Newton’s 1 st Law a) car suddenly stops and you strain against the seat belt b) when riding a horse, the horse suddenly stops and you fly over its head c) the magician pulls the tablecloth out from under a table full of dishes d) the difficulty of pushing a dead car e) car turns left and you appear to slide to the right

10. Examples of Newton’s 1 st Law

11. What is Friction? Friction = A force that opposes or slows down motion Caused by the physical contact between moving surfaces The amount of friction depends upon the kinds of surfaces and the force pressing the surfaces together Changes motion into heat

12. What is Friction? What are some ways athletes uses friction?