JOHANNESBURG: South Africans united in mourning for Nelson Mandela on Friday, but while some celebrated his remarkable life with dance and song, others fretted that the anti-apartheid hero’s death would leave the nation vulnerable again to racial and social tensions. President Jacob Zuma said Mandela would be buried on Dec. 15 at his ancestral home in the Eastern Cape. South Africans heard from Zuma late on Thursday that their first black president, a Nobel Peace Prize winner, had died peacefully at his Johannesburg home in the company of his family after a long illness. On Friday, the country’s 52 million people absorbed the news that the statesman, a global symbol of reconciliation and peaceful co-existence, had departed forever. Zuma also announced Mandela would be honored at a Dec. 10 memorial service at Johannesburg’s Soccer City stadium, the site of the 2010 W...