Short answers, pulled from the story.
North Germanic peoples originated from the Scandinavian Peninsula and are thought to have emerged as a distinct group in what is now southern Sweden in the early centuries AD. They are identified by their common use of the Proto-Norse language from around 200 AD, which evolved into Old Norse around 800 AD and later into the North Germanic languages of today.
Early medieval historians gave Scandinavia the Latin names Officina Gentium (Factory of Nations) and Vagina Nationum (Womb of Nations) because so many Germanic tribes traced their origins to the region. Groups including the Goths, Vandals, Burgundians, and Rugii all migrated from Scandinavia to the rest of Europe during the Iron Age.
Historians have proposed several causes: overpopulation, political tensions created by rulers like Harald Fairhair who drove men into exile, disruption of trade with the Abbasid Caliphate, fear of a Carolingian invasion of Denmark, and Charlemagne's destruction of Frisian naval power, which opened sea lanes for Scandinavian dominance. The Viking Age lasted from the late 8th century until 1066.
The Rus' were Swedish Vikings active in Eastern Europe, known to Slavs, Finns, Muslims, and Byzantines by that name, which is probably derived from rōþs- (related to rowing) or from the area of Roslagen in east-central Sweden. The Viking Rurik is believed to have founded the Rurik dynasty in the 9th century, which developed into Kievan Rus'. By the 11th century the Rus' had converted to Eastern Orthodoxy and were gradually merging with the East Slavic population, becoming the Russians.
Yes. Leif Erikson, son of Erik the Red, made what the historical record describes as the first documented trans-oceanic voyage in history and supervised the attempted Norse colonization of North America. His father Erik the Red had earlier discovered Greenland and overseen its Norse settlement in the late 10th century.
Germans called them Ascomanni (Ashmen); Anglo-Saxons called them Dene or heathens; the Irish used Finngall (white foreigner) for Norwegians and Dubgall (black foreigner) for Danes; Dubliners called them Ostmen (East-people); eastern peoples including Slavs and Byzantines knew them as Rus' or Rhōs; and Spanish Arabs called them al-Majus (fire-worshippers). The Old Frankish Nortmann became Normanni in Latin and Normands in Old French, giving both the Normans and Normandy their names.