Chapter 11-2 Gravity

Law of Universal Gravity All objects in the universe attract each other through gravitation force- dependant on mass and distance All objects in the universe attract each other through gravitation force- dependant on mass and distance Gravity 2 Gravity 2 Gravity 2 Gravity 2

Gravity Attractive force between two objects Attractive force between two objects Universal gravitation equation Universal gravitation equation F=G(m 1 m 2 ) d 2 d 2 Gravity Clip Gravity Clip

Gravity continued All matter is affected by gravity All matter is affected by gravity –Larger the mass the more the gravity –The closer the objects the more gravity

Earth- Very large-strong gravity. The moon is close enough to still be affected by its gravity but not as strongly as humans. Earth- Very large-strong gravity. The moon is close enough to still be affected by its gravity but not as strongly as humans.

Gravity con’t Acceleration due to gravity is a constant number – 9.8 m/s 2 Acceleration due to gravity is a constant number – 9.8 m/s 2 We will ignore air resistance so gravity is the same for all We will ignore air resistance so gravity is the same for all

Free fall and weight Free fall – to fall with only the force of gravity acting upon the object being pulled toward the center of the earth Free fall – to fall with only the force of gravity acting upon the object being pulled toward the center of the earth

Remember a bowling ball has more inertia than a softball so if we figure in air resistance it would affect the lighter softball slowing it down at the same speed as BB Remember a bowling ball has more inertia than a softball so if we figure in air resistance it would affect the lighter softball slowing it down at the same speed as BB

Weightlessness Apparent weightlessness Apparent weightlessness –When all objects are freefalling together toward the earth at the same rate –Example astronaut and shuttle

Weight - Amount of gravitational pull on an object. Dependant on the mass of the object - Amount of gravitational pull on an object. Dependant on the mass of the object W= mass x gravity (9.8) W= mass x gravity (9.8)

Weight The SI unit for weight is also Newton because the formula is mass times acceleration of gravity.

Terminal Velocity Final velocity that a falling object reaches because air resistance and gravitational pull equal each other Final velocity that a falling object reaches because air resistance and gravitational pull equal each other Skydiver-200m/hr parachute 120m/hr Skydiver-200m/hr parachute 120m/hr Space Jump Clip Space Jump Clip Space Jump Clip Space Jump Clip

Projectile motion Has 2 components Has 2 components –1)Horizontal motion- motion of an object that is in the direction and velocity it was thrown

Projectile motion 2)Vertical Motion- motion which increases due to gravity pulling the object toward the earth 2)Vertical Motion- motion which increases due to gravity pulling the object toward the earth