physics+review

=Gravity=
 * Gravity is a constant force exerted by objects that have mass. An object that has mas mass has gravity.
 * Your chair, your book, your pencil, and everything else all have gravity because they all have mass.
 * Your pencil only has a little mass so it only has a little bit of gravity so you can't feel it
 * However when you fall of your bike and you fall on the ground, its because the mass of earth is so great it pulls you towards the center of the earth.

Weight

 * Weight is the pull of gravity.
 * Weight pulls your body mass toward the center of the earth.
 * Weight is unlike mass.
 * Weight changes if gravity changes.
 * Weight is measured in pounds, kilograms, and ounces.

=**Weight** and Gravity on Earth and the Moon=


 * Weight is a measure of force of gravity of one object with mass pulling on the mass of another object.
 * An object on Earth's surface weighs more than the same object high above the earth's surface.
 * The farther you are from the Earth's center the less you weigh.
 * An object on the moon weighs less than the same object on Earth, because the moon has less mass than the Earth.
 * The weight of an object on Earth is greater than the weight of an object on the moon.
 * Objects on the Earth weigh about six times more than they would on the moon.
 * If there is no planet to pull on the object. The object floats and doesn't fall.

=Weight in Newtons= =Converting Kilograms to Newtons= =Converting Newtons to Kilograms=
 * Weight is measured in a unit force called a **Newton**
 * A standard pound is equivalent to 4.45 Newtons
 * So if a box weighs 100 pounds it weighs 445 Newton
 * If the box weighs 445 Newtons you divide by 4.45and you get 100 pounds
 * One Kilogram is pulled toward the center of the Earth with a force of 9.8 newtons.
 * To change kilograms to newtons, multiply kilograms times 9.8
 * To change Newtons to Kilograms you must divide newtons by 9.8