In March 1941 congress passed the lend-lease act, the Lend-Lease provided U.S. Military aids to foreign nations. July 1941, Roosevelt protested for a withdraw of Japan.
1941 Lend-lease act
In May 1942, from the 4th to the 8th was The Battle of the Coral Sea. That is where the Americans and Japanese aircraft carriers and planes clashed and fought.
After the great depression, the factories ran 24 hours a day producing tank, ships, jeeps, guns, and ammunition. But, in 1944 unemployment fell to 1%.
The Allies invasion of german-occupied France was the the first step to liberate Europe and also forcing Hitler to surrender. On June 6, 1944, American, British, and Canadian troops invaded France.
In 1945, the U.S. dropped an atomic bomb in the city of Hiroshima. When they blasted atomic bomb over 80,000 people were instantly killed. The two bombings caused Japan to surrender which lead to United States victory.
World War ll impacted the world economically since the United States developed the super-bomb. The super-bomb caused a monopoly because it was the most destructive bomb that was created.