This clip might be a bit old but is very useful to discuss the obstruction foul. To be more precise this video is from the 2010 World Cup in a game where Australia took the victory against Spain. In this video we can watch a sliding tackle by the Australian attacker and a foul that, for the umpire, ended up on a free hit for Spain. The question and the demand by the Australian player, is that after tackling the ball, the Spanish defender committed obstruction. What do you think?