Make all capitalization consistent with the rules of convention outlined in the American Heritage Dictionary. DO capitalize: The first word and any proper nouns in a title, heading, or subheading. Proper nouns, months, days of the week, but not the seasons.
Newton (unit) The newton (symbol: N) is the SI unit of force. It is named after Sir Isaac Newton because of his work on classical mechanics. A newton is how much force is required to make a mass of one kilogram go faster at a rate of one metre per second squared.
Newton's law of gravitation - (physics) the law that states any two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.