Gravity and Motion

How Earth revolves around the sun

in a nearly circular orbit

How the moon orbits the Earth

in a nearly circular orbit

force

a push or a pull

gravity

attracts all object toward each other

law of universal gravitation

every object in the universe attracts every other object

the unit used for gravity

newtons

the strength of the force of gravity depends on 2 factors

the matter of the object and the distance between the objects

Sir Isaac Newton

first scientist to realize that gravity occurs everywhere

Why dont Earth and the moon just fly off into space?

Because there is a force between the two that makes them stay together.

mass

amount of matter in an object

weight

the force of gravity on an object

the weight of an object

can change depending on its location

As the distance between two objects increases

the force of gravity decreases

Newton's first law of motion

an object at rest will stay at rest, and an object in motion will remail in motion until an outside force stops it

inertia

the tendency of an object to resist change in motion

more mass =

more inertia

inertia and gravity combined keep the planets in

orbit around the sun and the moon in orbit around the Earth

the force of gravity depends on

mass and distance