Female Vocalists: The only constant member of the Supremes from 1960-1978.?

Questions

What year did Yuri Gagarin become the first human in space?

On which day of the year would you 'firstfoot'?

In August 1945 atomic bombs were dropped on which two cities?

Approximately how long after the atomic bombs were dropped on Japan did they surrender?

In what year was Benjamin Spock's Baby and Childcare book published?