U.S. military power helped to bring the war to an end. The U.S. had enormous industrial strength—some of which had been supplying the Allies with weapons.
Due to the war industry in the US the women's movement progressed and the govt. adopted new diplomatic policies. Industry production boomed. Manufactures needed to keep up production for the war and this allowed more employment opportunities for women and African Americans.
In order to produce more materials, new technology was developed. Economy boomed as well. As the soldiers came home towards the end of the war, workers were less needed in factories. Raising unemployment after a time of industry and economic prosperity, lead to the Great Depression.
WW1 was the first widespread use of machine guns, air power, submarines, poison gas and armed vehicles. During the war, whole populations were conscripted on all sides to fight, while factories were changed to make war materils.