What gravitational force does the moon produce on the earth is their centers are 3.88x10(8)m apart and the moon has a mass of 7.34x10(22)

Isaac Newton compared the acceleration of the moon to the acceleration of objects on earth. Believing that gravitational forces were responsible for each, Newton was able to draw an important conclusion about the dependence of gravity upon distance. This comparison led him to conclude that the force of gravitational attraction between the Earth and other objects is inversely proportional to the distance separating the earth's center from the object's center. But distance is not the only variable affecting the magnitude of a gravitational force. Consider Newton's famous equation

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come closer and become far apart and become steam/gas

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up