U.S. stocks opened sharply lower on Monday as investors grew concerned that the emergency policy measures by global central banks over the weekend meant the economy is in much worse shape than previously believed.Instead of soothing the markets, another emergency interest rate cut from the Federal Reserve had the opposite effect.The S&P 500 opened down 8.1%. The index hit a circuit breaker after falling more than 7%. Trading was halted for 15 minutes.The Dow opened 9.7%, or 2,250 points, lower and the Nasdaq Composite fell 6.1%.Global stock markets also plunged on Monday as data showed the coronavirus outbreak has caused an unprecedented economic collapse in China.Markets were battered across Asia, with Australia’s benchmark index crashing nearly 10% in its worst day on record. In Europe, London’s FTSE 100 fell 8%, while France’s CAC 40 plunged over 10% and Germany’s DAX dropped roughly 9%.The European Securities and Markets Authority required short