If the value of US Dollar crashed the economy of the entire world will also down as most of the countries depend on USD and their economy may also depend on bitcoin therefore if the USD crashed it will effect all most all the economies of the world.
Nope I do think so, because if we see the crises in US dollars it would affect the USA region only. I think other countries would be safe I'm their economic balance. I think USA government may adopt the bitcoin that time make as the national currency.
the impact of the currency fall only slightly to the economy of the country as a example GBP now is currently falling but the British economy is still pretty good and it will be same with usd if usd fall does not mean usa economic will collapse.
I think if the currency of a country crashes then it occurs because of some issue in the economy of that country so first the economy will be crashed and after that USD will crash but it will not do any effect on other countries.
I don't think you have a very advanced understanding of economics. The USD is the baseline currency for the world and a large majority of trade agreements are made based on the USD rates. If the USD collapses the entire world is affected, like it or not. Trade agreements have to be re-designed, exchange modifications have to be made, and the US would experience a massive series of economic issues resultant from a weak currency in an import nation.