(a) One purpose of the speech: The speech encourages Americans to support space exploration. It shows the importance of being the first to explore space for peace and knowledge. It motivates people to accept difficult challenges, like going to the moon.
(b) One immediate historical effect on U.S. society: After this speech, the U.S. increased its space program efforts. It led to more funding for NASA and united people to compete in the Space Race with the Soviet Union. This pushed the country to achieve scientific progress quickly.
(c) One broader historical situation: The speech was given during the Cold War when the U.S. and the Soviet Union were rivals. They competed in technology and military power. The goal to go to the moon was part of this competition to show who was stronger and more advanced.