Oil prices fell for a second day on Monday as the dollar gained ground amid political uncertainty in the US.Brent crude futures fell 55 cents, or 0.7%, to $84.48 a barrel after settling down 37 cents on Friday.US West Texas Intermediate crude was at $81.65 a barrel, down 56 cents, or 0.7%.Last week, Brent fell more than 1.7% after four weeks of gains while WTI futures slid 1.1% as weak oil demand in China, the world's top importer, countered robust summer consumption in the US.Source: Qatar News Agency