VideoBoos for first lady Michelle Obama were heard amid the roar of engines before the start of the Ford 400 at Homestead-Miami Speedway. The boos could be heard as Obama and Jill Biden, wife of Vice President Joe Biden, were saying, "Gentlemen, start your engines" to begin the race Sunday, the South Florida Sun Sentinel in Fort Lauderdale reported. Obama and Biden, grand marshals for the race, were invited to NASCAR's final event of the season to bring awareness to their Joining Forces initiative, which supports military families. The women had addressed the drivers at a meeting before presiding over...