The 1920s were both a "roaring" and a turbulent decade for the United States. A thriving interest in all things modern--technology, jazz, social mores--clashed with a cultural backlash against growing multiculturalism and changing values.
A time of affluence. A time of fear. During Eisenhower's eight years in office, the United States fought a war in Korea, fretted about communism in Hollywood, and began a space program.
The 1960s might be the most tumultuous decade in American history, when simmering resentments boiled over into rage against the status quo. From the assassination of John F. Kennedy to the My Lai Massacre, after the bloody Sixties the United States would never be the same.
This video is from the Khan Academy subject of Math on the topic of Test prep and it covers 2010 IIT JEE Paper 1 Problem 50 Hyperbola Eccentricity.