Gravity

All matter is affected by gravity Gravity – a force of attraction between objects that is due to their masses All matter has mass, gravity is a result of mass, therefore all matter experiences gravity

Earth's Gravitational Force is Large Earth is so massive, it's gravity is very large You must constantly apply forces to overcome Earth's gravitational force

The Law of Universal Gravitation “Why do objects fall toward Earth?” “What keeps the planets in motion in the sky?” Sir Isaac Newton (1642-1727) The law describes the relationships between gravitational force, mass, and distance. It applies to all objects in the universe

The Law of Universal Gravitation All objects in the universe attract each other through gravitational force.

Gravitational force increases as mass increases Part 1 of the Law Gravitational force increases as mass increases

Part 2 of the Law Gravitational force decreases as distance increases The further away you are from an object, the less gravity you feel

Weight is a measure of gravitational force Weight and mass are different Mass – amount of matter in an object, and value does not change Weight– measure of gravitational force exerted on an object, value can change depending on location in the universe. Mass and weight are constant on Earth, so the terms are often used to mean the same thing! BE CAREFUL

Weight on Other Planets Multiply your Earth weight by: Your "new" weight Mercury 0.4 Venus 0.9 Earth 1 Moon 0.17 Mars Jupiter 2.5 Saturn 1.1 Uranus 0.8 Neptune 1.2 Pluto 0.01 Sun 28