Johannesburg - "Will you blow a vuvuzela in 2010" and "Do you believe that you are the Nelson Mandela of the 21st century," were among the questions South African schoolchildren put to US President Barack Obama this week, ahead of his first visit as president Africa.

Obama, the first US president of African descent, arrives in Ghana on Friday for a two-day official visit.

Ahead of his visit, he called on young people across Africa to send him questions and comments via MXit, a popular mobile social network, and SMS.

In South Africa, the Independent Newspapers group is also collecting questions.

One of the group's papers, The Star, gave a flavour of some of the questions on Wednesday.

After FIFA president Joseph Blatter said last month Obama had accepted an invitation to the opening game in the football World Cup, one unnamed pupil wanted to know whether he would try his hand at the vuvuzela.

The plastic trumpet blown by South African football fans caused a ruckus during the June Confederations Cup, with some European players and sports commentators complaining it was "too noisy."

Another pupil was preoccupied by the HIV/AIDS pandemic that has ravaged the African continent.

"If you could offer advice to orphaned children living with HIV/AIDs, what would it be?" Obama was asked.

Most of the questions, however, pertained to Obama's personal life and tastes, including: "Would you ever attend a P-Diddy concert?"(dpa)