I hope to study and complete all your notes from this presentation to remember all what did we say in the class. Good Luck.

1. Forces of Nature Gravitational Magnetic

3. Net force (Combining force); It is the total amount of Force, ( minus the forces that cancel each other out ). Force of gravity Force of muscles Net force

4. Balanced Forces Unbalanced Forces When the net force is Zero. -> NO movement When the net force is NOT Zero. -> movement

6. 50 N 100 N 100 N 50 N 50 N 50 N

7. Balanced or unbalanced? Action Reaction Gravity Inertia Friction

8. Gravity balanced UN Time (mSec) Speed (m/s) BALL Ground

9. Inertia balanced UN Time (mSec) Speed (m/s) BALL PUTTER

10. Friction balanced UN Time (Sec) Speed (m/s) SKATE

17. Gravity and Motion Free Fall Free fall- when gravity is the only force acting on an object (free fall acceleration is directed toward center of earth) The acceleration of gravity ( g ) for objects in free fall at the earth's surface is 9.8 m/s 2 . Galileo found that all things fall at the same rate in the absence of air resistance, regardless of their mass

19. Projectile Motion When an object is thrown into the air, two forces and two motions affect the movement of the object. The object may be thrown horizontally with a certain force, but the vertical force of gravity combines to affect the motion. Slow projectile - shoot a monkey Fast projectile - shoot a monkey

20. Projectile Motion seconds 0 2 1 3 Velocity (m/s) forward downward 0 50 9.8 19.6 29.4 39.2

21. Projectile Motion seconds 0 2 1 3 Velocity (m/s) forward downward 0 50 9.8 19.6 29.4 39.2 49 48 47 46