I am starting this thread to add up general topics, questions and information related to US history.Most of the material will be taken from different sources.
correction and discussion is welcome.I hope this helps.

Q:How Could the United States afford to enter WWII right after great depression?

Ans:The U.S was totally unprepared for what became "World War Two". That is, while the U.S had begun to send aid to Great Britian it wasn't until Japan attacked Pearl Harbor in 1941. The war in Europe began with the invasion of Poland but really gained major momentum when Germany attacked France.

1939-1941 the U.S military ranked a few spots down from the top in military capability and was indeed preoccupied with recovering from the Great Depression. it took until 1942 before the U.S sent Patton to North Africa to combat Rommel's Afrika Corps and even then the Americans lost battles because of lack of arms and equipment.

it was necessary for the government to declare rationing and to campaign to sell war bonds to get the money to wage the war.

The Depression represents a temporary drop in everything so the war actually accelerated economic recovery from the Depression. by Dec 31st 1945 the United Sates Real GDP jumped to 2.22 trillion Dollars, from Dec 31st 1941 of 1.41 trillion. by 1950's 27.3% of the worlds GDP was contributed by the United States

The U.S not only paid for its war debts, it was the greatest player in the rebuilding of both Western Europe, Great Britain and Japan.
The only Allied country who won but paid compensation was the USA, to Japan. In 1988, under the Civil Liberties Act, U.S. President, Ronald Reagan, apologized to the Japanese-Americans interned in camps during World War II and agreed to pay $20,000 to each surviving former detainee.

statistics source :http://www.multpl.com/us-gdp-inflation-adjusted/table

this a report of congressional research service, dated June 29th 2010.
the report includes Military Cost of Major U.S wars, value at the time of conflict and in today's price, % of economy share.

https://fas.org/sgp/crs/natsec/RS22926.pdf

The 105-country Outer Space Treaty signed in 1967, Outer Space Treaty bans the stationing of weapons of mass destruction (WMD) in outer space, prohibits military activities on celestial bodies, and details legally binding rules governing the peaceful exploration and use of space.till august 2017, One hundred and five countries are states-parties to the treaty, while another 26 have signed it but have not yet completed ratification.

What they didn't count on was the US Air Force's most simple weapon ever: a tungsten rod that could hit a city with the explosive power of an intercontinental ballistic missile (ICBM).

During the Vietnam War, the US used what it called "Lazy Dog" bombs. These were simply solid steel pieces, less than 2 inches long, fitted with fins. There was no explosive — they were simply dropped by the hundreds from planes flying above Vietnam.

Lazy Dog projectiles (aka "kinetic bombardment") could reach speeds of up to 500 mph as they fell to the ground and could penetrate 9 inches of concrete after being dropped from as little as 3,000 feet.

The idea is like shooting bullets at a target, except instead of losing velocity as it travels, the projectile is gaining velocity and energy that will be expended on impact. They were shotgunning a large swath of jungle, raining bullet-size death at high speeds.

That's how Project Thor came to be.

Instead of hundreds of small projectiles from a few thousand feet, Thor used a large projectile from a few thousand miles above the Earth. The "rods from god" idea was a bundle of telephone-pole-size (20 feet long, 1 foot in diameter) tungsten rods, dropped from orbit, reaching a speed of up to 10 times the speed of sound.

The rod itself would penetrate hundreds of feet into the Earth, destroying any potential hardened bunkers or secret underground sites. More than that, when the rod hits, the explosion would be on par with the magnitude of a ground-penetrating nuclear weapon — but with no fallout.

It would take 15 minutes to destroy a target with such a weapon.

These days, not so much. The Bush administration even considered revisiting the idea to hit underground nuclear sites in rogue nations in the years following 9/11. Interestingly enough, the cost of a single Minuteman III ICBM was $7 million in 1962, when it was first introduced ($57 million adjusted for inflation).

The trouble with a nuclear payload is that it isn't designed to penetrate deep into the surface. And the fallout from a nuclear device can be devastating to surrounding, potentially friendly areas.

A core takeaway from the concept of weapons like Project Thor's or (hyper velocity rod bundles) as defined in a USAF strategic document, is that hyper sonic weapons pack a significant punch and may be the future of global warfare.


source:
http://www.businessinsider.com/air-f...n-force-2017-9
https://www.armscontrol.org/factsheets/outerspace
https://www.theatlantic.com/technolo...he-sky/488024/