Gravity
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http://www.solarspace.co.uk/Earth/earth.htm |
Newton believed that the simple law of universal gravitation was the frame of the universe. This law states: Every material object attracts every other material object with a force that is proportional to its mass and inversely proportional to the square of the distance between them (Berlinski 134-135). |
The Law of Universal Gravitation can be
represented with the following equation:
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During the process of developing the Law of Universal Gravitation, Newton undertook a great thought experiment. He first thought of the following concept: could the orbit of the moon be the result of gravitational force? He believed that this might be true because the acceleration caused by gravity could change the velocity of the Moon. Which. in turn, would result in the moon following in an orbit around the earth (cite).
This lead to Newton's cannon on a mountain idea. Newton knew that if a cannon was placed on a high mountain and fired, the projectile would follow a curved path towards the earth. This curved path would be the result of the forces of gravity and the powder's explosion acting on the projectile. If the muzzle velocity of the cannon was increased, the projectile would travel further and further before falling towards the earth. Newton came to the conclusion that if the projectile was fired at exactly the right velocity, it would travel completely around the earth. During this time, the projectile would continuously be falling in Earth's gravitational field (cite).