useless trivia: What Word Means: A First Name - A Variant Of Collar?

Questions

In a period of 400 years how many times does the 1st of January fall on a Sunday ?

In the Gregorian calendar after 10,000 years by how many days will the calendar be wrong by ?

In the kama-sutra the art of which game is recommened for women to study ?

In which field of science is the history of the universe studied ?

In which month is the Earth nearest the Sun ?