Basics of Astronomy essays

Basics of Astronomy essays #1) (A) Issac Newtons Law of Universal Gravitation is: Two bodies attracted to 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. This means that the further apart these two attracting bodies are from each other, the less the gravitational force between them is. The force of gravity depends on the product of the mass of the two attracting bodies. If the distance between the two bodies doubles, the force between them becomes one quarter of the force it was before. The Law of Universal Gravitation is vital because it mathematically proves Keplers Three Laws of Planetary Motion. The Planets follow the same laws of motion as objects on the surface of the earth. (B) Newton discovered other types of orbits that have circular of elliptical paths. However, if the velocity of an orbiting body were increased, its orbital path would change to a parabola or hyperbola and it would escape the gravitational pull of the sun. It would then leave the solar system. Parabolas are the orbital paths of objects in the form of an open curve. If one cuts out an angle in a circular cone, it would follow this path parallel to the sides of the cone. Hyperbolas occur when a plane cuts across two parallels half-cones. Keplers laws applies to any situation where two bodies in the universe orbit each other due to their mutual gravitational attraction, not just two planets. For example: Moons that orbit planets, such as the four Galilean Moons that orbit Jupiter. #2)(A) The reflecting telescope, which uses a mirror to attract light was perfected by Isaac Newton in 1668 although it was developed by John Gregory in 1663. The refracting telescope, which uses a lens to attract light was developed by a Dutch optician in 1608 named Hans Lippershey. Two other inventors were Zacharias Jannssen and Jacob Metius. However, Galil...

African Americans in Vietnam W essays

African Americans in Vietnam W essays Fighting on Two Fronts: African Americans and the Vietnam War, begins by briefly looking at how previous wars such as the American Revolution, WWI, WWII, and the Korean War dealt with race relations in comparison to the Vietnam War. Earlier wars had a segregated system that limited the contact between white and black soldiers, and it was not until the Vietnam War when soldiers were fully integrated. In a chronological order beginning with the draft and ending with the soldiers returning home, Westheider examined how full integration brought about many problems for the US military. Prior to writing about racial discrimination in the Vietnam War, Westheider collected enormous amounts of data that ranged from official government documents to journal entries from soldiers. Over nine hundred personal interviews from white and black soldiers of varying ranks helped ensure the accuracy of his reports. The extent of racial conflicts depended on many things including the setting, the per sonnel, and the timing of military events. Despite the sensitivity of racial issues Westheider remained objective and allowed the reader to form their own opinions about the US military and their handling of racism against African Americans in the Vietnam War. Beginning with the draft, the reader is overwhelmed by the enormous amount of statistical data. Westheider discusses in a chapter what could have been best explained with a series of graphs. Earlier chapters focus on numbers while later chapters add a human element to the Vietnam experience. The draft and recruitment requirements were said to favor the middle and upper class which meant, African Americans were being drafted in disproportionately high numbers because of their lower social and economic standing. It would be useful if the reader knew what percent of Americans were eligible for service, which would put the number of black recruits in perspective. Westheider assumes...