Newton’s Law of Universal Gravitation

1. Newton’s Law of Universal Gravitation By: Erin Stickles, Tyler Young, and Johnny Baird http://videos.howstuffworks.com/hsw/19121-exploring-gravity-the-law-of-universal-gravitation-video.htm

2. Universal Gravitation • Universal Gravitation: Two bodies attract each other with equal and opposite forces • The magnitude of this force is proportional to the product of the two masses and is also proportional to the inverse square of the two bodies.                ,

3. The idea of gravity was Introduced by Sir Isaac Newton in the late 1600’s • Born December 25th , 1642 • He was a scientist who combine ideas to explainhow the universe operates • Newton used Galileo's ideas and further explained them

4. How He Discovered it • Newton’s law of Gravitation was discovered while he watched an apple fall from a tree • He said that the force that pulled the apple to the ground was the same force that keeps the moon and earth in it’s orbit

5. When thinking about the apple falling from the tree he wondered if the same principle of gravity could be used outside of earth. • He calculated the force needed to keep the moon moving in orbit around the earth.

6. What is it used for • Gravity keeps us grounded • Astronomers find out other planet’s gravity so then satellites can be put into their orbit. • Without gravity if you would throw a ball in the air it would keep going out of earths atmosphere and float deep into space forever.

7. To put a satellite in a planets orbit you need to project the satellite at a speed to where it is able to stay the same distance away from the planet's surface as it moves horizontally.

8. Fun Facts • Even though the Earth's pull on the moon is greater than the moon's pull on the Earth, the moon's gravity does affect the Earth. It's the main factor for the oceans' tides • Astronauts grow several inches out in space without the force of gravity pulling them down, but back on Earth they shrink back to their original Earth height.