How much damage can Saudi Arabia do to the United States economy if they started selling their Oil using another type of currency rather than the US dollar?

what is a speculative attack on a currency. How does it work. Provide a real world example.

It is very important to the leaders of Dionland that people can make any trade they wish to using their national currency of Paulbucks. If this is the case, what policies would the Impossible Trinity suggest they might follow? What would they be giving up in each case?

If you were responsible for marketing CAT scanners worldwide (average price, $1,200,000) and your country of manufacture was experiencing a strong and appreciating currency against almost all other currencies, what options are available to you to maintain your competitive advantage in world markets?