1. Gravity

2. Gravity • Gravity - The attractive force between ALL objects in the universe • Newton’s Law of Universal Gravitation – all objects in the universe attract each other by the force of gravity

3. Strength of Gravity • The strengthof gravity depends on: • Mass- The more mass an object has. The greater the gravitational force.-Example: Planet vs. Star • Distance- A the distance between 2 objects increases, the attraction between them decreases.

4. Center of Gravity • The point at which all of an object’s mass APPEARS to be located. • An object is balanced if its center of gravity is supported • If it is not supported the object will fall

5. Free Fail • Galileo Galilei Experiment 10 kg 100 kg • Two cannonballs dropped off a tower at the same time • One ten times more mass than the other • Both cannonballs land at the same time • Gravity accelerates both objects at the same rate.

6. Gravity and Free Fall • All falling objects meet air resistance (fluid friction) • Because of shape and air resistance some objects will fall slower than others • Leaf, Feather, Paper Objects fall at a rate of:9.8 m/s2(acceleration)

7. Terminal Velocity • When the pull of gravity is equal to the air resistance it no longer accelerates and is in what is called terminal velocity.

8. Projectile Motion • Projectile motion- path of a projectile • Projectile- an object that is thrown in the air • A projectile moves forward due to its inertia and accelerates downward due to gravity Once you release the ball either directly downward or horizontally, the force acting on it is gravity