United States:
Economy: It impacted because they had to produce goods to support the war efforts and overnight the unemployment went down and dropped tragically to 10%.
Politics: It expanded the federal government which also affected by challenging and giving opportunities to civil rights and women's movements.
Technology/science: The technology in military weapons created new uses, conflicts, which surrounded that technology. It also allowed the creation of new products, better medicines, and scientific exploration to grow.
Japan:
Economy: They were devastated; large cities except for Kyoto, industries, transportation were severely damaged, the war wiped out many of the gains that Japan had since 1868.
Politics: The Government changed because Japan surrendered and it was now rebuilt with U.S. forces; Japan was disarmed, the empire was dissolved, the way the government was before all changed to a democracy, and it's economy and education system reorganized and rebuilt.
Technology/science: They got some technology from the U.S. since they were allied now; weapons were advanced, ships, aircraft, submarines, vehicles, transportation, tanks, chemicals, and atomic weapons. All this helped Japan rebuild stronger.