A player takes a long throw towards his opponents penalty area. The
goalkeeper and an attacker challenge for the ball but they collide and
both of them miss the ball which now bounces towards an empty goal net.
Just before the ball enter the goal a defender deliberately punches the
ball clear. Describe exactly what you would do now?
This was a deliberate hand ball by a defender in his own penalty area so stop play and award a penalty kick. You should also caution the defender for unsporting behaviour. You do not send him off for denying a clear goal scoring opportunity because a team can not score directly from a throw in. In fact the defender was not too smart here. If he had just left the ball to enter the goal, the goal would of been disallowed and play would of been restarted with a goal kick
An attacker takes a penalty kick and his shot hits the crossbar and
rebounds straight to him. Before he can take a second shot he is fouled
by a defender. Its a clear penalty but do you send off the defender for
denying a clear goalscoring opportunity? Explain your answer.
No. The attacker can not play the ball twice before another player touches the ball so this is not a clear goal scoring opportunity. However you could still show the defender a red card if you consider the foul as serious foul play, otherwise show the defender a yellow card for unsporting behaviour.
After a quick counter, a striker rounds the goalkeeper who then
deliberately brings him down outside the penalty area. But there is a
covering defender on the line. Do you send the keeper off?
The keeper has clearly denied an obvious goalscoring opportunity, so yes, show him a red card. It is irrelevant who the striker still has to beat – whether it's a defender on the line, or a goalkeeper. Restart with a direct free-kick outside the penalty area after you have made sure another player or a substitute keeper has gone in goal.